Ahh,

I too have followed the instructions as given, and have the exact same problem. Interesting. My site is new and at the latest version. The changes are saving. I have changed to the new name as instructed and then changed back. Changing to the new name gives me the Welcome to Zen Cart page, changing back to admin lets me back in.

I will hit it again tomorrow and let you know if I figure anything out. Right now, my brain needs a rest. Please post if you find the solution. Like you, I am pretty comfortable that I am doing things correctly, so...

I'll keep you posted.

Regards