I have same problem. Works OK if "redirect form data" not selected.
File Upload doesn't work either.
UPDATE: I can now get files to both Upload and attach to email. However the file name,
both in the upload directory
and in the email attachement have a code injected. For example: the file named "your_ad_here_blue.gif" is changed to "your_ad_here_blue_4caf6cae666f5.gif".
Where is the "_4caf6cae666f5" coming from? What is it?
UPDATE 2 I found out what is for and am now pleased to see it. Thanks CK

I feel more secure.