Invalid Action, the selected action was not valid error in ms crm 4.0

If such kind of error Invalid Action, the selected action was not valid in ms crm 4.0 while loggin in or else already logged in and trying to acces any record or doing some action,
then just try to make the MSCRMAsynchronous Service up.
Even if its showing started in the services, just restart it.

This is a way i hv solved.

yes.sudhanshu