Please double-check that you are using the 'svcore' folder from the SimpleViewer-Pro download zip package ('simpleviewer_pro_2.3.2/web/svcore/') and that you are uploading it to the correct location on your web server, overwriting the existing Standard 'svcore' folder ('wp-content/plugins/wp-simpleviewer/svcore/').
If you are in any doubt as to whether or not the existing Standard 'svcore' folder on your web server is being overwritten with the Pro 'svcore' folder, then try deleting it from your web server first before uploading the Pro version in its place.
Once the 'svcore' folder has been replaced, the plugin will have no option but to use the Pro files and the SimpleViewer branding will be removed.
For reference (and for others reading this post), instructions for upgrading WP-SimpleViewer to SimpleViewer-Pro can be found here.
SimpleViewer Support Team.