referred back to login, after choosing product in admin edit mode

Just recently my site started to act up, referring me back to the login page each time I try to update a product in my site through the administration edit mode.

Any ideas?

did you find any error message in log?
if you got "Validation of viewstate MAC failed." error,
you have to specify the machineKey in your web.config.

Error Message in Log:
See Below

CommonError  
Severity:  11  
Message:  Resource string is not found  
Exception:  System.Exception: Resource string (admin.configurationhome.acl.description) is not found. Language ID=7  
IP address:
Customer:  
Page URL:  http://www.creativeventures.biz/Store/Administration/ConfigurationHome.aspx  
Referrer:  http://www.creativeventures.biz/Store/Administration/GlobalSettings.aspx  
Created on:  5/9/2010 8:54:53 PM  


This is the current error when I try to register back in as the administrator ( I took out the IP Address and Customer for Privacy Reasons)...

the error itself means the "admin.configurationhome.acl.description" is missing in database, however i don't think this is a build-in value in database, you may try to change it to "Admin.ConfigurationHome.ACL.TitleDescription" which will return you the value "Manage access control list."

hope this helps.