The server and the system having hardware address xx-xx-xx-xx-xx-xx have conflict for ip address x.x.x.x
Warning: Duplicate IP address in use. Contact your administrator.

I have (2) Node servers and (2) Data servers, all on Netware 6.5sp5
All machines are static coded IP Only
-No rogue machines

The Node servers are clustered, and mirroring to both data servers for redundancy
Each node has a separate GroupWise function, again for redundancy

Up until about a month ago, my nodes suddenly freeze with the above error
My config hasn't changed when it started, and I am now pulling my hair out

The NICS were set at Auto/Auto along with a unmanged Gbic switch
I recently changed the NIC configurations to 100/Full, and also moved over to a managed switch also coded at 100/Full.

Additionally changed:
"CPU Hog Timeout Amount=8 sec" to "CPU Hog Timeout Amount=1 Min"
changed config.sys: FILES=150 and BUFFERS=100

Any suggestions ?
Any troubleshooting tips ?