I am also having this issue with 1.3.9h where I get bumped out to the admin home page when I try to insert an option in the Attributes Controller. I have added many modules and customized many files to this site. And perhaps it isn't even a problem with a modified file - but instead with a file that was corrupted during upload.

Can you tell me where to look, in general, to re-upload files to repair this. Such as, "probably the problem file is in admin/includes". Or something like that, so I can narrow my search down?

Thanks!

~anne