Unless you bought TCB in the few months after it was first released, the Holding Vats secret room should not be a problem for you.
Unless you've modded your game, you can tell which version of TCB you have by looking at the pressure plates. If the pressure plates in your game look just like the pressure plates in the H&S room images for TCB, then you've got the "
3.1"
version of the TCB hold, and the Holding Vats secret room is solvable in the normal way.
If you've got the old different-looking pressure plates, then you've got the old "
3.0"
version of the TCB hold, and the Holding Vats secret room is insanely hard. But not to worry. If you paid for the full TCB game, you don't have to pay again for the newer version. Email your purchase info to support, and they will send you a new download link.
More information about the secret room, and the new and old versions of TCB is
here.