Is your server a PC?

Have you got keywords running? I believe that Keywords were disabled for PC's when they would no longer work Mac <> PC.

We run 5.3.2 for Macs with a Mac server (just a mini Mac) on OS10.4 and all PC's talk to the Mac server very nicely (sans Keywords for PC's) direct or via the internet. As you say it does lock up occasionally, even after restarting several times and then next time all is inexplicably OK.

I do agree with the instructions - you really need to trawl the FAQ and then some - Now seem to assume that some of us know all and leave out the vital ingredient but Now Help seems to be very good.
Melbourne - Australia GMT +1100