Okay, after fiddling around a bit more I contacted the support and they found some issues. Aparently permissions for the public_html folder were changed, and I am not sure if I did it accidently (which would be odd - I never make changes to any of the preconfigured files on my webspace) or those changes were introduced by one of the themes I tested.
Anyway, I can run GS now, however, I have to disable the htaccess file altogether (not sure why it's not working; but I have to comment everything out before I can access my page).
@moped: I have no direct access to Apache's error log.
@shawn_a: At some point I deleted all files that were in my webspace, except for a simple html file that had just one line of text in it, and a php file returning phpinfo() data. I still received a 500 server error, so I'd say that definitely had nothing to do with any htaccess file.
Anyway, I can run GS now, however, I have to disable the htaccess file altogether (not sure why it's not working; but I have to comment everything out before I can access my page).
@moped: I have no direct access to Apache's error log.
@shawn_a: At some point I deleted all files that were in my webspace, except for a simple html file that had just one line of text in it, and a php file returning phpinfo() data. I still received a 500 server error, so I'd say that definitely had nothing to do with any htaccess file.