RRAS service not stopping

Hello,

I am facing the problem with the RRAS service. My code tries to open a
RAS connection. Before opeing the RAS connection it stops the RRAS
service and starts again. This logic iterates till the RAS connection
is not opened. Once the RAS connection is open it will not start and
stop the service. If the CDMA modem is not able to switch to 1xRTT
mode the RAS connection is closed. so the logic is as follows

timer ( 60 secs )
{

if ( RAS Connection is open )
{
if 1xRTT
{
}
else
{
close RAS
}
}
else
{
stop RRAS
start RRAS
open RAS
}
}

Problem
--------------------------------
When the signal strength is low (this is my observation), This works
fine for 4-6 hours. after that the the code returns error while
opening the Ras connection. The RAS connection never opens. when I
cheked in the windows services, the Status of the Remote and Routing
Access service is stopping.

Error log
----------------------------------
I am logging the error from the RAS API's into the event logs.
following is the summary of that log.
First error in the event log is "Error Code = 691 - Access was denied
because the username and/or password was invalid on the domain.".
After this error, the connection never opens and the event log
contains series of "The RPC server is too busy to complete this
operation." errors

Is there any way I can stop the RRAS service forcefully. As there are
many critical applications running on the computer I can not restart
the computeer.

My machine configuration
-------------------------------------------
Windows XP embedded - SP2


Thanks in advance
Yuvraj