The .81a patch borked my install as well. On start up I got the vanilla splash screen plus the fs_gladius error. Checked the RTW folder and it's size was decreased to 2.4gb as well. Wasn't using the wrong installer as I blew the previous ones away right after use. The .81a patch is erasing some parts of the EB install.

The full .81a install over a clean copy of 1.5 is working fine.