Can't always log into admin

[Hostile]

My user account has admin privileges.  If I want to enter the admin panel right after I login it works fine.  But if I move around my site for a while and then try to access the admin panel I am prompted for my password and it's never accepted.  I have to logout of the forums, then log back in for me to get into the admin panel.

Has anyone experienced this? I tried searching but I wasn't successful.

[ThorstenE]

sometimes the usergroups aren't converted properly. this article should help you:
I accidentally deleted my admin account, what do I do?

[tuliaoren]

I met the problem too. Thank you very much TE. It's very helpful.

[Hostile]

Ugh, I'm a complete idiot.  It helps if you are using the correct password to login.  Thanks for the response TE.