That action could not be completed.

[nextgen]

I have upgraded my vBulletin 4.2.2 to the version 5.0.5.
So far all it works well except for this message

That action could not be completed. Please try again, and if this occurs again please contact the system administrator and tell them how you got this message.

I should clarify that this error get me when I'm connected using an account that is not administrator.
This error not happens with my administrator account, the error occurs at any page upon user login.

[Wayne Luke]

Are your forums turned on?

[nextgen]

Yes, If you want I can give the link by private message.

Edit: Amazing the error has been fixed, I have not touched anything and now if it is working correctly.