Errors with on a Windows 4.0 network

We have four graphic artest where I work. The problem, which is becoming worse, is as follows:

Jane (on computer 1) creates a quark 4.1 document called “documentA.qxd”. Saves document to server. Then, John (on computer 2) later tries to open that it to make chages to that document. When ever John(on computer 2), Jim (on computer 3) or Jason (on computer 4) try to open “documentA.qxd” their computers crash, but if they go to Jane’s computer, the document opens up just fine. If john logs on to janes computer, he can open the documentA, but if jane logs on to johns computer, you get the Doctor Watson Error and quark automatically quites.

HELP!!!!