Hi,  I have a DNN 4.0.2 portal which can no longer upload files via the file manager.  If I log in and go to File Manager, I can browse for allowed file types, add them to the upload list, but when I click 'upload new file', the page refreshes but the file does not get uploaded.  I get no error or any other message - it gives the impression that it's worked.  The file does not appear physically in the filesystem either, and I'm talking about new files here (i.e. not trying to overwrite existing files).  I'm trying with .jpg and .pdf files, both of which are in the allowed list of file types.

I tried toggling the permissions on the portal folder (i.e the Windows permissions) and found that having taken away modify rights from ASPNET, then given them back, I was allowed to upload one file, then it stopped working again.  I gave aspnet full permissions and was allowed to upload one file again, then it stopped working once more.  Current state is that aspnet and network service have modify rights on the portal root folder but I cannot upload any files.  This used to work fine and nothing has been changed on the server to my knowledge. 

Any clues as to what is wrong here?  Are there any other permissions that should be set up (not that that would explain why it has suddenly stopped working!!).

Thanks in advance