V49
Mark I
Internal error: Oops: 0

Okay, I see what's wrong. Looks like I was just slightly too aggressive with the memory scrounging.

Mk2 players can have 1/2 drives, on a single ide controller.
Mk1 players have TWO ide controllers! Cool. Anyone got 4 drives in their Mk1 player yet?

v51 fixes this problem (v51 is identical to v50 for Mk2 players).