500 error on bulk import

Hello:

I did a clean install of this on two sites that had previously been 2.6 sites. Instead of upgrading them I just deleted them and started over.

The first site I did when 2.7 was first released, and everything works fine.

The second I did today after downloading a fresh copy of 2.7 (presumably with a few bug fixes, as the file size was slightly different) and I notice that the bulk file import is coming up with a 500 error. Everything else seems to work ok.

I use Php SuExec on my server which lets php run on virtual sites as the user of that virtual site instead of user "nobody". This results in tighter security because I only have to chmod files to 755 in order to have the server be able to write to them. But it sometimes results in 500 errors if I try to configure anything to 777.

This isn't the case here but I thought I'd mention it. The files in the admin folder are actually set to 644.

Any idea why just the bulk import is giving me a hard time on this site?

I think it's something with the "includes" ... I uploaded the includes folder from the first site to the second, and it works fine now.