#181 Internal error on open nonexistant dir

[irix]

I run xxdiff:
xxdiff synan/Dicts graphan/Dicts/

Dir synan/Dicts exists and graphan/Dicts/ do not
exists. So xxdiff fails with
--cut--
$ xxdiff synan/Dicts graphan/Dicts/
xxdiff (app.cpp:626):

Internal error.

There has been an internal error within xxdiff.
To report bugs, please use the sourceforge bug tracker
at http://sourceforge.net/tracker/?group_id=2198
and log the above information above and if possible,
the files that caused the error, and as much detail as
you can to reproduce the error.

--cut--

If I run (no trailing slash):
xxdiff synan/Dicts graphan/Dicts
everything is ok, and xxdiff says:
--cut--
xxdiff (util.cpp:492):
Cannot access file: synan/Dicts/Dicts
IO error: No such file or directory
--cut--
It's normal behaviour