You can set up the fixsub.tcl script using the "touch /etc/SubTest" copmmand but if you don't have a serial cable the only other option is to pull the drive and mount it in your PC. You'll have to use a Linux boot disc and then mount your partitions using Linux commands. Check the Newbies Guide to Hacking the Tivo on instructions for doing this. You'll find the link for it in the How Tos Only sticky on page 3 in the file downloads posts. My advice, either make a serial cable or buy one from 9th Tee. If you're serious about hacking a DTivo you're going to need some way to communicate with it and putting the drive in your PC each time can be a real PITA.
Please don't PM me or any other members looking for personal assistance. You'll do better by posting (after you've exhausted the search feature, of course) and taking advantage of the collective expertise of the membership instead of a single individual that may or may not be able to help you. Thank you and enjoy your stay at DDB!