unavailable figures make Frame crash

[Jakob Fix]

Hello,

we have the following problem on a couple of machines, with different documents:

If, on opening a file with missing figures, the user chooses to skip
this (and possibly all other figures), Frame crashes.

Occurs on some machines, not all of them.  Frame is +SGML 5.5.6,
Windows is 2000 or XP.

Any ideas why, and how to fix this?  Thanks in advance.
--
cheers,
Jakob.