'with-open-file' bug? (in MCL 1.3.2)

[CXEA000 <CXEA@MCGILLA.BITNET>]

Hi,
   I've just discovered an exasperating bug (is there any other kind?):
it appears that 'with-open-file' will not work on an LC under system
6.05 using MCL 1.3.2. I get a 'file not found' error, even though the
':if-does-not-exist' keyword is ':create'. I am sure the bug is not
mine for two reasons: because my program runs perfectly under systems
6.07 and 7.0 on the SE on which it was developed, and because even a
very simple test fails in the same way on the LC only.
   Has anyone encountered this? Is there a fix? My next step, of course,
is to try running my program on the LC with system 6.07, but this is
not an entirely satisfactory solution as I will soon need to have my
program running on a variety of Macintoshes, and I want to be sure it is
going to run. Please help me soon, as I am scheduled to demo my program
to someone else on Tuesday May 26th, on an as-yet-unknown machine
confguration, and I would really like the demo to go smoothly...

           Thank you for any help you can give on this stupid problem...
                  Chris