WP-SimpleViewer is compatible with WordPress v3.3.1.
Do you have any other plugins installed and activated (whether on the incompatible list or not)?
If so, try temporarily deactivating them to see if this makes a difference.
Also, if you are not using the default WordPress theme, try temporarily reverting to the default theme to see if this makes a difference.

I found the problem. I deactivated "WP Security Scan" plugin and it worked.
Now I have to figure out why...
Luis

I have just installed and activated WP Security Scan v3.0.9 and can still create WP-SimpleViewer galleries successfully (the 'Add Gallery' button still works).
I do not know why this plugin seems to interfere with WP-SimpleViewer in your WordPress installation but at least you have found a workaround.
Another workaround would be to create your gallery on your computer using svBuilder, upload the complete gallery folder (not just the contents) to your web server via FTP and embed the gallery in a post using one of the two methods described here: http://simpleviewer.net/simpleviewer/su … l#external

The "Sociable" plugin is causing the same conflict...
http://wordpress.org/extend/plugins/sociable/

I tried disabling multiple plugins (which use jQuery). When I disabled the Sociable plugin, everything worked fine. The site is using a custom-built theme. However, that shouldn't matter in the admin side. I suspect that Sociable's option additions to the post/page creator in the admin are what caused the conflict. I could tell that jQuery wasn't running in the SimpleViewer window because choosing "Wordpress Library" didn't hide the Flickr fields.

Select Add From Server    Add From Server
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Plugin to allow the Media Manager to add files from the webservers filesystem. Note: All files are copied to the uploads directory.
Version 3.2.0.2 | By Dion Hulse | Visit plugin site
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Used by millions, Akismet is quite possibly the best way in the world to protect your blog from comment and trackback spam. It keeps your site protected from spam even while you sleep. To get started: 1) Click the "Activate" link to the left of this description, 2) Sign up for an Akismet API key, and 3) Go to your Akismet configuration page, and save your API key.
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Out-of-the-box SEO for your Wordpress blog. Options configuration panel | Upgrade to Pro Version | Donate | Support | Amazon Wishlist
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Simple Banner Rotation Program for *** Theme of WP
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Powerfully integrates Constant Contact into your WordPress website.
Version 2.3.1 | By Katz Web Services, Inc. & James Benson | Visit plugin site
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Create fancy-lookin' forms for the Constant Contact API plugin that have tons of neat configuration options.
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Just another contact form plugin. Simple but flexible.
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Save form submissions to the database from Contact Form 7 and Fast Secure Contact Form. Includes exports and short codes. | Data | Settings | FAQ
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Generates a fully customizable sitemap
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This Plugin adds a simple downloads manager to your blog.
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Integrates FancyBox by Janis Skarnelis into WordPress.
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Based on Luke Howell's quote rotator, the flexi quote rotator allows you to add the quotes to your site using a shortcode or php snippet in template instead of only as a widget. Also adds flexibility with styling and setting durations.
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This plugin makes it simple to add Google Analytics to your WordPress blog, adding lots of features, eg. custom variables and automatic clickout and download tracking.
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Parses Google Calendar feeds and displays the events as a calendar grid or list on a page, post or widget.
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This is not just a plugin, it symbolizes the hope and enthusiasm of an entire generation summed up in two words sung most famously by Louis Armstrong: Hello, Dolly. When activated you will randomly see a lyric from Hello, Dolly in the upper right of your admin screen on every page.
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Displays all links of a certain category in a post using a shortcode, according to a definable template. Includes optional Facebook Like button.
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A javascript media viewer similar to Lightbox and Thickbox. Supports all types of media, not just images.
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Push the title attribute from the img tag to the anchor tag
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Automatically add links on your posts, pages and RSS feed to your favorite social bookmarking sites.
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Extends the User Photo plugin to allow the generation of square thumbnails. (Requires the User Photo plugin, WILL NOT WORK otherwise.)
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Display and rotate random quotes and words everywhere on your blog. Easy to custom and manage. Ajax enabled.
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Themes the WordPress login, registration and forgot password pages according to your theme.
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Allows themes to be previewed without activation
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Allows users to associate photos with their accounts by accessing their "Your Profile" page. Uploaded images are resized to fit the dimensions specified on the options page; a thumbnail image is also generated. New template tags introduced are: userphoto_the_author_photo, userphoto_the_author_thumbnail, userphoto_comment_author_photo, and userphoto_comment_author_thumbnail. Uploaded images may be moderated by administrators.
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Enables Cufón font-replacement in WordPress - After installation you only have to put your generated font-files to /wp-content/plugins/fonts/ directory. Go to the Settings Page for more instructions and to add your own replacement scripts.
Version 1.6.10 | By Tobias Battenberg | Visit plugin site
Select WP-SimpleViewer    WP-SimpleViewer
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Create SimpleViewer galleries with WordPress.
Version 2.3.0 | By SimpleViewer Inc. | Visit plugin site
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Easily upload any type of content without the need for FTP. You can even upload plugin and theme archives and have the files automatically extract into the plugin or theme folder.
Version 1.0.11 | By Chris Jean | Visit plugin site

It looks like you are using Sociable v3.0.3.8. Try upgrading to the latest version (v4.2.6).
Make sure that your WordPress installation is also up-to-date (v3.3.1).
As stated, I have tested Sociable v4.2.6 alongside WP-SimpleViewer v2.3.0 and there does not seem to be a conflict between the two on my WordPress v3.3.1 installation.
If upgrading does not help, try temporarily deactivating all your other plugins leaving only Sociable and WP-SimpleViewer activated to see if this combination works.

I appreciate that you are trying to trace the root of your problem but by having so many plugins active and by only deactivating one at a time, you may not gather enough data to find conclusive proof. There may be interactions between other plugins that are also contributing to the problem.

There seems to be something in the fact that WP-SimpleViewer does not work when you have Sociable activated but that WP-SimpleViewer does work when you deactivate Sociable (even with all the other plugins you have activated).
I appreciate you posting such information as it may well help other users who face the same problem.

However, having tested both plugins together, all I can report is that there does not seem to be a direct conflict between Sociable and WP-SimpleViewer.

That would be helpful. In any case, you have highlighted a possible conflict which may help other users and you have found a workaround which enables you to continue using WP-SimpleViewer (temporarily deactivating the Sociable plugin) so, thank you for that.

Dear admin,

FYI, I have discovered "Instapress" plugin also have conflict with WP-SimpleViewer.

thanks