Is it maybe my graphics aren't being exported? I selected export and compress files into jar at the option screen, but no luck.
If you want to check whether the graphics are in the jar or not, either use jar tf
at the command line or rename it to .zip
and open it with your favourite unzipper.
But the typical problem here is getting the structure for the resource path wrong. If you want help debugging, it would be useful if you post the relevant snippets of code, the relevant snippets of the jar structure, and the exception message.