I don't think this has as much to do with the script as it is with my host, but my host moved me to a new server and now whenever I try to upload an attachment with mybboard (and also with every other upload script I have), I'm getting a 500 Internal Server Error. I tried to resolve this with my host, but they're support is too shitty to figure out the error. Now I'm asking you guys if any of you have had the same problem and what you did to solve it.
How is the upload URL defined? Might there be some differences in the directory structure on the new server vs. the old one? Could there be something wrong with the directory / file-permissions? Who is the owner of the upload directory?
I'd be happy to take a look into it for you. I have experience in debugging scripts and server bugs. Please message me on one of my given chat clients.