AVG antispyware inactive on Guest account

Hi: I have the last version of AVG antispyware 7.5.1.43 plus when I'm in the administratoe accout all is ok but in the Guest Account it remaind inactive when I try to activate it it say failed to activate resident shield.
I take a look in the error.txt and that is :

[2008-06-29 18:26:25] Error: cannot open service control manager, Value: 00000005, Position: .\GuardCheck.cpp, 204

could someone tell me why? have avg solved the problem?
I sow many people having troubles with the activation of the shield
but in my case is only within the guest account.

Astorcito