Hmm, the grey screen thing is odd, should not have done that.
So let me see if I have this right, the server share is maped to a PC and a Mac, the files there can be seen by both. Files created on the PC show up on the Mac, but files created on the Mac don't show up on the PC (or the server?). Have I got it right?
Silly question, are you sure you are saving the file in the right place on the Mac?