error with large uploads

[Medtech]

i was uploading a 10.5 meg file and keep getting this error. usually i was able to upload 16 meg files with no problem

Your submission could not be processed because a security token was missing.

If this occurred unexpectedly, please inform the administrator and describe the action you performed before you received this error.

using vb 3.8.1

any suggestions?

[Lynne]

Does this happen only with the large files or any file you try to upload? What version were you using prior to 3.8? (Also, you realize that 3.8 is in beta stage and is unsupported.)