dial up error 633 in vista

I have the following problem:
when i try to use a dialup connectcion with a modem (i've tried with 2
different modem) in my notebook i have the ras error 633.

If i open the modem with a terminal i can interrogate succesfully,
also in the rpoperties of the modem the diagnostic is ok.

I have tried to enable the ras log and it seems unable to open the com
port.

i have scanned with all anti-virus/dialers, etc but no results.

how can i re-install ras client ??

the modem drivers is vista compatable (one is internal one is on a
express card).

i have tried to unnstall antivirus/firewall (kaspersky7), to logon as
a new user, enabling disabling services, etc.etc.

please help me