10.3.9 Server AFP problem (with 10.4.11 clients)

Hello, I am an Apple System Engineer and have been assigned a task. I need to shed some light on a serious problem that has occurred in the last 3 days. I am running an XServer 10.3.9 with 50 10.4.11 clients (I know… I know). All updates to the 10.4.11 (and 10.3.9 server) have been performed. The AFP service on the server (and replica) fails at will with an up time of about 2-3 hours – the longest is about 10 hours. It seems that both servers do this, so this must be a problem on the client side? All the clients have been re-imaged in the last 2 weeks with a new image (OS, adobe, work apps and all). They have been working fine for two weeks (new image applied to them), and this week this just started to happen.

I been trying to gather info on what could be causing this. If anyone can help shed some light, please do.

Gordon