However "preachy" this post may appear, it is quite apparent that many users are quilty of failing to "Read the Manual"
Were they to do so, they would read that "TMG V7 IS NATIVE TO THE MISCROSOFT VISTA OS", using any other OS version may and has caused a miriad of install issues as posted here.
Knowledgeable TMG users anticipated a new version of TMG to coincide with the new MS OS Vista, these two programs compliment one another and based on experience I recommend the use of TMG V7 with MS Vista exclusively.
After all, using upgraded/updated software will make ones PC experience user friendly in the long run !