I have something to check for Jarvis and his error showing in the UIError.log... From what he posted all the UI Checks are looking at:
%EQDir%\Uifiles\\
I have to wonder if his UI_CharName_XX.ini file has the double box in place of the UI name. Having that will cause the UI to default back because it doesn't know what UI folder to look at.
Just something to check.