Description on categories not saving properly

Hi
I am in the process of writing out category information and when I go to save the screen goes back to the sign in.

http://dezertdezinez.com/store

I would like to know if this is part of a permission setting that it's not saving or if there is something else that is causing this.

thank you

It should not be a permission item as you would not see the screen at all if you did not have permission

Is this a new install or an upgrade?

upgrade from 1.5.0 to 1.5.1

How did you upgrade form 1.5 to 1.51??
Procedure...

How long are you taking to write your descriptions? If you do not click on a page for 15 minutes, the admin session will time out. It doesn't realize that you are working in the editor.
It is recommended to write your text in an external text editor, then copy/paste it into the category/product text box so you do not take time there.

kobra:

How did you upgrade form 1.5 to 1.51??
Procedure...

I followed the update instructions and copied files from the drive to the server as needed .

copied files from the drive to the server as needed
Where did you read "as needed"??

Normally, a complete file set is loaded so I suspect that you might have missed something