JTAG Server dies!

I have Q6.1 on a Dell Optiplex 745 Pentium D with XP. I'm debugging code for a Nios II processor. Everything seems fine but every 30 minutes jtagserver.exe dies. The Administrative Tools Event Viewer reports the following:

Event Type: Error

Event Source: Service Control Manager

Event Category: None

Event ID: 7016

Date: 3/12/2007

Time: 5:14:29 PM

User: N/A

Computer: TAUTREYDT

Description:

The Altera JTAG Server service has reported an invalid current state 0.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp (http://go.microsoft.com/fwlink/events.asp).

I've tried to find something on my PC that could be causing this. I've turned off the virus protection, unplugged the network, tried a USB wired keyboard and mouse (my PC has Bluetooth wireless KB & M). I even tried reinstalling Quartus. It still dies every 30 minutes! The time may shift but it stays consistent for some time. If it's dying at xx:15 and xx:45 I can start the service at xx:13 and it'll predictably die at xx:15. Has anyone else experienced this behaviour?