On a Mac Os workstation (10.2.8 or 10.3.3), logged in as Administrator.

If I use mount_afp on the Mac (Using an NDS userid that has full rights to
all volumes) to mount one volume - all works well. However if I then use
it to mount a second volume - the first one becomes invalid. If I mount a
third - likewise the second one becomes invalid. The icons on the desktop
disappear leaving only the last one mounted - the content of which is
fully accessible.

You are then unable to mount the invalid ones again (either by using
mount_afp or by using the GUI Go - Connect to server) without restarting
the Mac. Oddly though if you only use Go - Connect to server, you can
mount as many as you like without problems.

Doing ls -l inside the /Volumes folder reveals :-
ls:m1: Invalid argument
drwx------ 28 admin unknown 908 May 15:29 m2

showing that m2 the second mount is still there, but m1 has somehow
gone 'funny', and is no longer valid or useable.

This is a major problem because we use Mac Administrator v3 and this is
exhibiting the same problems, hence why I went down to basics and
experimented with manually mounting multiple volumes in a terminal session.

Is it possibly a fault of the afp nlm ? or Mac OS X ? and is there any way
round it ?