One of my users is trying to uploading a JPEG file but when they submit it, they get the Cannot find server or DNS Error page. I think it might be a problem with file size or dimension, but why does it result in showing the generic error page rather than a Coppermine error page?
Some errors can not be "caught" by coppermine's error handling mechanisms, e.g. if a user tries to upload a file that is just to large it will make the script time out, resulting in a generic error page the browser generates that says something about various error resons (including dns issues). Just put some text on the upload pages, telling users not to upload files larger than xxx bytes (you'll have to find out what is a save file size for you).
GauGau