Outlook 98 cannot attach file, lack of resources

[Henrik]

Running outlook 98 under win 2000 on a network. No
exchange server.
When attaching a file lying on the network, sometimes get
the message that a file cannot be attached because of lack
of resources.
Same message sometimes appear when saving an attached file
on to the network.
We have tryed to rename the file or save it on a local
disk or save/attach it from a library tree that is not
very deep.
These things actually very often help - but does not solve
the problem.
Any good ideas ?

Thank You in advance.

Henrik