Thank you...Thank you...Thank you...
Sure enough, it ended up being the images\frontend\epilepsy.dds file that was missing from the Default directory. The other file that's referenced from the default directory is images\frontend\splash_logos.dds according to the eq2ui_loginscene.xml file so I just copied both from the other system over to the Fetish folder so that I won't lose them again.
Sorry that I didn't mention the fact that I had removed my Default directory in it's entirety prior to running the Full File Scan but it just didn't even cross my mind. I know better than that but I was so wrapped up in looking for custom file variations in dates, sizes and content.
Thank you both for you help on resolving this issue. Now I can go back to relaxing without having to feel so bad for having screwed something up. Plus, now I have the better looking splash screen back.