Communication error with server

Hi everyone,
I am trying to access the worklist using the below code:

SourceCode.K2ROM.Connection myConn = new SourceCode.K2ROM.Connection();
SourceCode.K2ROM.Worklist myWList;
try
{
myConn.Open(k2Server);
}
catch(Exception)
{
return;
}
myWList = myConn.OpenWorklist("ASP");

This works for all users except one. When I log in as a particular user, the application throws an error
'Communication error with server'
for SourceCode.K2ROM.Connection.Worklist.Open
This user has all the permissions on the process.
Please someone help me solve this ...
thx
sree