Frustrated by Plug-In Installation

[BellaHHD]

Well ... I'm just going to step away from it for a bit before I manage to wreck everything that DOES work.

This is what I have:

Simple Image Gallery, 2.5.3 (I've deleted all other plugins for the time being)

2 directories:

squareit-gallery - CHMOD 777
squareit-loadtab - CHMOD 777

and

squareit-gallery.php - CHMOD 755
squareit-loadtab.php - CHMOD 755

I am using "Fancy URLs" and yes, mod_rewrite is enabled on the server.

Clicking the "image Gallery" tab on the Plugins page takes me to this

Very frustrated.

I know it's probably something very simple.

:: sigh ::

Thanks again for the help.