There's probably more discussion about TCC over at Celestial Heavens than there is here, so I went there to see if there was a posted answer. I did a brief search -- your luck might be better -- but I did see that quest problems are somewhat common. I found two possible issues:
First, TCC was designed to run with GreyFace's patch. I've no idea how difficult it is to get that correctly installed on modern OSs.
Second, you might try going to jail for two years so the dungeon respawns and you get to try again.
If nothing else, maybe you could use an editor to give yourself the skill. Please share your experiences here. Thanks!