On Windows 2003, the service was crashing continuously. As soon as I would start the service, it would error out with "1067: Service terminated unexpectedly". The way I resolved it is by the following.

c:
cd \progra~1\websense\bin
XidDCAgent -s
XidDCAgent -c

Wait about 30 seconds, then press 'Enter'. Now the DC agent should start as expected.