mod_rewrite error on install on 1.5

I'm attempting to do a brand new install of 1.5 and am running into the mod_rewrite error. I've been searching the forums and have checked all the things I've found in them. mod_rewrite is definitely enabled and the .htaccess files are in the root directory and install dir just as they were when they were unzipped.

The funny things is that I can unzip 2.0.4 and it installs perfectly. But when I wipe it all out and attempt 1.5 I get the error.

I'm at a loss as to where to look next. Any ideas would be appreciated.

I'd double-check that the correct .htaccess file is there. the 2.0 and 1.5 versions are very different, and sometimes it doesn't get deleted when expected.

I have verified that they are the correct .htacccess files. I did notice this morning that when the error is thrown the URL is http://diyhistory.lib.iastate.edu/install/

I don't know much about .htaccess files but I would guess this means that the .htaccess file in the root directory is successful but somehow is failing on the .htaccess in the install directory. Of course I could be way off.