Hi
Engine version has nothing to do with the version of the software. The current engine is 4.1.60, the next will be 4.2.40.
NetShield 4.6 is certified for NetWare 4.x, 5.x, 6.x
If you had this problem for 12 months I suggest that you contact McAfee support.
I could not find anything in their KB/Service portal regarding hangings when unloading on NetWare.
Cheers
AVDude