Easiest way would be to upload the old package to http://www.smfhacks.com/smf-package-parser.html and get the file edits.
Ok, that sounds great, you'll have to be more specific in what I should do though, steps please
Not everyone is a savy computer expert.
EDIT, I have now downloaded the EZportalpack to my computer, run it through the parser.
Found the changes needed to be done in the "./Themes/default/languages/Modifications.english.php" removed the stuff, still get the "test failed" when trying to uninstall.
I also get test failed in "./Sources/ManagePermissions.php"
Try to find the lines the parser suggests, don't even have those lines in there so I cant remove them :-), problem still there.