I have installed XOOPS and can access the site as well as login with my admin account. When I try to make changes to the General Settings under Preferences Main I get a blank page and when I refresh I get "No valid security token found in session"
I can make changes to any other settings, including 3 loaded modules(xHelp, Extended Profiles and Private Messaging) without errors.
I know I am missing something but can't seem to find it.

I am trying to access both from the localhost and from a remote machine. All works except the General Settings.
The site is in the trusted sites on both computers.

Windows 2000 with latest service packs and hotfixes
XOOPS: 2.1.1
Apache: 2.0.54
MySQL: 4.1.12
PHP: 4.3.11
Zend Optimizer: 2.5.10

I am not enabling the SSL, I have even tried to save without making any changes and still get the above behavior.

As you can see a brand new install. All went well thanks to the docs on this and the XOOPS documentation site.

Well, 2.1.1 isnt a stable release btw.
So if you are using it for a production site, dont.
Use XOOPS 2.0.10 Stable