windows remote assistance "cannot make a connection"

[slimdig11]

i'm using windows vista. when i try to invite someone to help using windows remote assistance, error message comes up saying "remote assistance cannot make a connection. the information entered could be incorrect or you might not have a valid internet connection. verify the information that you entered, verify that you have a network connection, and then try again." i try disabling all firewalls/internet security, make sure properties are set to allow remote connections, etc. but doesnt have any effect. also, i can connect and give help to other computers fine, but i cant connect when i need to be helped. same error message comes up when i select email method or invitation file method. other computers on home network can connect both ways with each other so router is not problem.