I am currently working for a company that has a backlevel version of Silktest (6.0 Sp3 on a New Windows XP Pro box).
There are real problems here .. some of which I have a workaround for a few of which I do not. Basically it's really an uphill battle. I am having problems recording a window (alot of times I don't get everything).
I get playbacks that fail with control not responding ESP with HtmlCheckbox.
If anyone looks at my specs and has a "oh I know the problem solution where":
(1) The os is too new (maybee I should try windows 2k instead)
(2) The version of silk is way too low (I should try 6.5 or 7.0)
(3) Thats just the way stuff works with silk and Java Script .. live with it kid
Id say you should go for the second option. I have not recorded anything on XP. But we too use XP Pro - Vmware Image Silktest 6.0.2 SP2 the tests run perfectly over there.
I would not suggest the 3rd option of living with it since there usually is a workaround although finding the workaround might stretch your tolerance limits.
There is a similar post of XP having problems with Silktest in the Segue forum.