Steven,
problem is solved
It was my cache that was not deleted properly so it seems

Steven Speirs wrote:

What version of WP-SimpleViewer are you using?
I have just upgraded to WordPress 3.4 and have successfully been able to create and view a gallery created with the current version of WP-SimpleViewer (v2.3.0).

Please post the URL to your gallery so that I can take a look.

I use SV-v1 the advanced version of Versie: 1.5.4, because of my subdir /wp-content/photos/

I thought it was because I used ï instead of i in the name of the gallery but changing that was of no use
www.catterycelizes.nl/wp-content/photos/aicha/ (is where the gallery is)
http://www.catterycelizes.nl/honden/aicha/ (is where the gallery should appear
and thanks again Steven for looking in to this

After upgrade WP to ver 3.4 I can't make new galleries
The gallerie itself is made but when placing the code op a page or post I get the message:" gallery not found"
older gallery's are published fine