Same thing happened to me

I ordered InstantCake last night for my TCD 540040 and I got the same exact error. The reason is that it is expecting your new upgrade drive to be located at /dev/hdc and for some reason, even when I setup the drives correctly, it still couldn't locate it and my drives were showing up as hdf and hfg. I set the cdrom to primary slave and the new upgrade drive as secondary master. (single drive upgrade not dual). Since my drive was not hdc it gave me that error. It would be nice if they could add something to the script/install that says something like "Your drive was not detected on hdc, please select the HD Letter where it can be found" and use whatever I enter, such as hdf. I ended up using the hinsdale "DD" (direct copy from one HD to another) copied my orginal tivo drive to my upgrade drive which took about four hours, then ran the msfadd command to expand the new drive so it can use the new bigger space. Everything went perfectly and now i still have my newest tivo software version 7.2 with the extras like yahoo and fandango and I still have all my recordings, season passes, etc. By far that was the easiest way to go, I just couldn't seem to figure out how to make the backup file and restore it. Four hours is a long time to wait but not having to set everything up and wait a few days for the channel logos and software update to re-download is worth it. I used a 200g drive and the tivo is seeing all of it. Woot! =) The only hassel was the new drive (Maxtor Diamondmax 10) is much louder but I used a program on a floppy called "feature tool" made by Hitachi that lets you change the acoustic management of the drive to make it quieter if the drive supports it and mine did. After I re-powered up the tivo with the new upgrade drive for the first time the drive was contantly reading and writing and clicking away for hours. This morning the activity of the drive has calmed down and isn't as annoying but I'm seriously thinking of getting a quieter drive, maybe a Maxtor Quickview like the tivo original drive was cuz that thing was whisper quiet.

KB3's response was the key to solving the problem.  Using the BIOS to check was how I finally got the connections made properly.  It is obviously critical to get the Primary and Secondary IDE connections correct along with the jumper settings on the drives.  Once you get those connections correct, the software works like a dream.