ssolis5788:
I've gone back and double checked that I removed all the files from the incorrect version and they are gone. Even through I uploaded the files from the correct version, I still cannot access the control panel. I do not know what else to try... Any help is most appreciated!
What FTP software are you using? What version zencart? It sounds like something got deleted that is part of the core.
Does your FTP software have the ability to "synchronize"?
BACK UP YOUR FILES FIRST.
Then re-extract your zencart version, and try to synchronize the admin folder to the server. It should give you a list of changed files. Note that you don't want to over write your custom define pages.
One lesson to learn here is NEVER (sigh) install a mod to a live site. Always work within a sub-directory that has a working copy to test on first (and with it's own database and copy of data). I actually have multiple backups running in subdirectories. Main Site is in ROOT, then a full working backup in a sub-directory, and usually 1 or more testing directories.
This way I can test a mod and just over-write the directory and restore the database if there are problems.
I am beginning to think that perhaps your issue isn't EP 1.2.5.4 related. Nothing in the mod should affect your ability to login to the admin. But perhaps a file on your server got corrupted.
If your really stuck and at a loss, leave me a pm and I'll see what I can do to help more directly.
-chaddro