Vista - Internet explorer accessing problem

Hello,

We are curently buliding functional test suite by means of the Watin
framework.

We are experiencing problem when requesting web site in the Internet
Explorer in our tests.

Case when all is working

When we request web application locally on the server running test by nunit
console everything works fine.
Internet Explorer is opened, Password Chalenge appears and thorugh WatiN
proper credentials are filled in (Windows Authentication).

Case when the same test is not working

When we try to run it remotely triggering CruiseControlTray to make web
application request by means remote call to CruiseControl.Net NT Service
which calls WatiN, then it throws:
WatiN.Core.Exceptions.TimeoutException : Timeout while Internet Explorer busy

Presumably this may be some security issue.

Any pointers would be much appreciated.