Mac OS X 10.7.2, NIS 5.1 (up to date)
My iMac crashed tonight with a kernel panic. Nothing notable in the console log preceeding the crash.
Sat Dec 24 23:53:25 2011
panic(cpu 1 caller 0xffffff80002b353b): Releasing non-exclusive RW lock without a reader refcount!
...
Kernel Extensions in backtrace:
com.symantec.kext.SymAPComm(12.0f224)[10C799D0-520B-8DA4-3F56-19915132C700]@0xffffff7f80750000->0xffffff7f80753fff
dependency: com.symantec.kext.internetSecurity(1.4f19)[97986347-80B9-3C60-BB05-F98AD49D115D]@0xffffff7f807ab000
BSD process name corresponding to current thread: SymDaemon