File upload problem

It's more likely a 500 Internal server error. If you turn off friendly HTTP error messagesin IE you will get an accurate error message which should help locate the problem.

However, I can tell you that most upload issues are permissions related. Make sure that the upload folder has read, write, and modify permissions on it.

This is an AspUpload error, so the AspUpload documentation may give a clearer anwser, but looking at the issue it looks like your web host may have disabled the SaveVirtual method. You should contact your web host to find out.

The SaveVirtual method is required so that the upload can first be saved to the servers memory so that it can be checked for file type, file size, filtered for malicious code, chekc the file doesn't already exist, etc. before it is saved to disk. Without it uploads would be very insecure with no control over them.