[daip] POSSM hangs

[Gustaaf van Moorsel]

After starting POSSM (to plot cross-correlation spectra) it hangs and
needs to be aborted.  This is in 31DEC07.  This worked not too long (a
week or so) ago, and it still works in 31DEC06 and 31DEC05.  The only
output in the message window is:

POSSM (release of 31DEC07) begins

This is on a 256 channel spectral line dataset, almost all adverbs are
at their default.

Gustaaf