[daip] LWPLA rpoduces output file when it shouldn't

[Gustaaf van Moorsel]

When running LWPLA, directing the output to a file using OUTFILE,
and specifying a non-existent PL version number, LWPLA fails, as
expected, with the error that the specified plot version is not
found.  However, it *does* produce the specified output file, of
size 0.  Clearly, in this case, no output file should be produced
at all.  Not a biggie, but might be worth fixing.  Thanks!

Gustaaf