[Five]

re-download the trial to another folder, then try installing from that one. do an md5 check on both versions of the trial, if they're the same then that 99% means that a) your installer is not corrupt and b) it won't work with Vista.

at that point, fire off an email to the guys who make DVD Lab pro and tell them about your problem... maybe a fix is coming up in a few weeks, who knows. or maybe your letting them know will motivate them to fix compatability with Vista.

another option is to downgrade to XP!