Hello,
This is really frustrating, any help would be greatly appreciated.

Creating new accounts works fine.
However, when an old customer tries to log in, it doesn't work sometimes.
On my pc, I can log in with firefox, but not explorer.
On another pc, I can't log in with either browser.

So, on my browser:
Explorer (doesn't work)
When the login is wrong for any reason (email or password), then it shows a small triangle with an exclamation point in the middle above the login fields. No red field and no text "Error: Sorry, there is no match for that email address and/or password"

When the login is correct, then it just redirects me to the home page (not logged in). I'm not sure how to turn off the error redirect.

Firefox (works)
With a login error, it gives the correct red field and error text.

When the login is correct, it lets me in.

I'm using a fresh version of 1.3.8a, but have tons of mods, including encrypted master password, which supposedly works with 1.3.8
I have played with it some more and got Explorer to allow login of old customer. I'm not sure, but it could be that I cut the session id out of the url. Or maybe not. I have duplicated the problem once by trying to login simultaneously on 2 different computers, but that doesn't always seem to cause problems.

This is really playing with my head. Any help is appreciated.