Hmm, Google suggests a re-installation of the program is normally expected to solve that problem. Since it hasn't helped you, I'd wonder whether a corrupted installation is preventing TI from un-installing correctly, so the corruption is being preserved into the new installation.
Unfortunately Version 8 is four versions old, so isn't really being supported any more. There is a cleanup utility, but it's for later versions, and only says it "may" work for older ones:http://kb.acronis.com/content/1727
Unless someone else has a better idea, it could be worth trying, but of course there's some chance it could create a disaster - since you have TI, I assume you have backup images of the system and a bootable TI recovery CD/DVD?