Compilation error in VSPASS3

[Ghgadfn]

Compiling a Pascal program (VMS game MONSTER), I got an error when the
compilation was almost done.  Running VSPASS3, I got after a while:

   *** Error -- Bad Block ***
   *** Value = 97 ***
   *** Value = 97 ***
   *** Error -- Bad block ***

Any idea what this could mean?  We can't find any information on it.
It is definetely no disk error.  We checked.

Any suggestion would be welcome.  Just post to the list.

Regards,
Kris Van Hees.