[LoadUIWeb] active directory authentication

I successfully recorded and played back load tests on our test environment as a practice run. I then proceeded to record on the Live environment, the reason for the testing in the first place. In the LIVE environment I get 401 warnings back from the majority but not all of the requests, no matter what authentication details I put in the authentication Information. having scrabbled around for info all day yesterday and today I come to the forum as a last resort. any idea anyone?

we use AD and I also put in logon details for our ASP server and the PC the tests are run on.