I've got a uVAX-II with DEQNA ethernet, and I'm trying to get it to netboot.

I've got the mop server running on my linux box, and the mop server says
everything is happy...  However, when I go to netboot, I get this:

>>> b

  2..
?4F SCBINT, XQA0
?06 HLT INST
    PC = 000C0E0A
Failure.
>>>

mopd says the load has completed, but I don't know what a SCBINT is,
or what it's caused by... (The manual says it's an "Unexpected SCB
exception or machine check.")  I recently yanked a tape controller and
moved the disk controller up a slot, perhaps that broke something?

Here's my slot layout:
1: KA630
2: 4MB ram
3: M9047 / empty
4: M3104 -- 8-port async
5: M7546 -- TK50 controller / M7504 -- DEQNA
6: M8639 -- RQDX2 disk controller

----
  Aaron J. Grier  | "Not your ordinary poofy goof." | agrier@poofy.goof.com
  agrier@reed.edu |  agrier@metro.grumblesmurf.net  | ...!reed!vla!agrier
  DECBEE65 0DEE3A0C 1ED7F54D 9E023CC4 and 0x0663D1A9 at a server near you.