This indicates an attempt to exploit a Buffer Overflow vulnerability in a print provider installed by Novell Netware Client.
The vulnerability is caused by the "nwspool.dll" library's failure to properly handle overly long arguments to the "EnumPrinters()" and "OpenPrinter()" functions. A remote attacker can exploit this to execute arbitrary code.
Novell Netware Client 4.91
Novell Netware Client 4.91 SP1
Novell Netware Client 4.91 SP2
System compromise: Arbitrary code execution.
Apply the update issued by the vendor: