I just found a similar problem being on almost all tested computers my PM generated Simpleviewer gallery works fine. 600 pixel images, with 5 or 6 lines of text. But on some computers the same texts are running out of the flash becoming invisible. This seems not to be a browser or a system issue since out of 3 windows users only one experienced it and out of 2 linux users only one too.
If you have basic knowledge on HTML editing you can quite upgrade these galleries, but differences and incompatibilities of browsers can easily cause a headache. Almost none of them measures, displays, works the same way as the others.