Abend in nfsgw.nlm

We have a NW5.1 Server with the NFS gateway running. We have just started getting a few abends, any ideas as to what is causing this?

Server BSESVR1 halted Monday, 9 April 2001 10:20:39 am
Abend 1 on P00: Server-5.00g: Page Fault Processor Exception (Error code 00000000)

Registers:
CS = 0008 DS = 0010 ES = 0010 FS = 0010 GS = 0010 SS = 0010
EAX = 00000004 EBX = 00000005 ECX = 00001260 EDX = 00008386
ESI = 0000931E EDI = D59B7260 EBP = D4ACCD1E ESP = D4ACCC20
EIP = D55D0626 FLAGS = 00010202
Address (D55D0626) exceeds valid memory limit
EIP in UNKNOWN memory area
Access Location: 0xD55D0626

Running process: nfsgw 1 Process
Created by: NetWare Application
Thread Owned by NLM: NFSGW.NLM