Remote Assistance not working

I can Ask for Remote Assistance but cannot offer/answer one, Error I get is
"The invitation from ***** to start using Remote Assistance is declined
because the program is disabled or is not installed on your computer.Go to
http://www.microsoft.com to see more information about obtaining this
application."

I checked on the web, found some articles about enabling the Remote
Assistance, floowed them all but no solution
One more wierd thing, the check box is Remote tab of System Properties is
unchecked everytime I open the it, I check it but then clicking on Advanced
button does nothing, I click Apply and OK, and then when I open System again,
Its unchecked again

Thanks and Regards
Rob