Ofcourse, it may have nothing to do with NAV, perhaps it's just that the snmp class (from westhawk) doesn't work with JDK 1.5.

Actually, we don't use the Westhawk SNMP stack anymore, so this might be the problem. We now use the Java SNMP stack from here:

http://edge.mcs.drexel.edu/GICL/people/sevy/snmp/