Unfortunately, this is a limitation of Adobe AIR (the platform on which svBuilder-Pro runs) and there is no way around the problem (other than to resize your images first).
Adobe AIR uses Adobe Flash Player as its runtime environment and the largest image size which Adobe Flash Player can handle is 16,777,215 pixels. This equates to a square image of 4095 x 4095. Please see this web page for details.
If you have images larger than 4095 x 4095, then you'll need to resize them in an imaging program (such as Adobe Photoshop) before feeding them to svBuilder-Pro to create your gallery.
There are, however, other methods of creating SimpleViewer galleries which you might like to try which do not have this image size limitation. A list of other ways to create SimpleViewer galleries can be found here.
If you find that you still see this error message for an image of less than 16,777,215 pixels, please upload it somewhere and provide a download link so that I can try to replicate the problem myself and hopefully help further.
Also, if you are trying to add many images at once, Adobe AIR may not be able to allocate enough memory for the task at hand. Even if your computer has plenty of free RAM, Adobe AIR applications are limited to around 1GB of memory allocation. Try adding your images in smaller batches to see if this helps.
I realise that this may not solve your issue but I hope that it at least explains the nature of the problem.
SimpleViewer Support Team