C333g, I hope you are using truecrypt sensibly (i.e. only for truly sensitive information, for which you have copies elsewhere, also encrypted, but have verified that both copies can be read)
I say this because I can think of few worse ideas than a system which is fully-encrypted, when the inevitable MS ****-up or invasive crap-ware gets to work. This is because often the only sensible thing when your PC will not run properly is to mount the HDD in another PC and extract the important data before a complete re-format and install.
Known conflict with Truecrypt is ExIFS drivers.
As to hubbly59139 problem, I tried this in google search 'not working with SP3' but quailed in the face of 40 or more pages referring to a vast variety of applications. Maybe the programs are mentioned in there. BUT the one thing you dont appear to have tried is a complete re-install, am I right? If your registry contains some old, long-forgotten reference which is causing this trouble, then installing, uninstalling re-installing just a service pack is not going to help !! I wont express surprise if you tell me your XP was an upgrade to Win2K, but I will be surprised if a full re-install does not provide a cure.