My machine gave a panic

I upgraded it to freebsd6.2. I got a panic again. Debug info as below; What do I have to change ? Thanks # kgdb kernel.debug /var/crash/vmcore.0 [GDB will not be able to debug user-mode threads: /usr/lib/libthread_db.so: Undefined symbol "ps_pglobal_lookup"] GNU gdb 6.1.1 [FreeBSD] Copyright 2004

My machine gave a panic

I upgraded it to freebsd6.2. I got a panic again. Debug info as below; What do I have to change ? Thanks # kgdb kernel.debug /var/crash/vmcore.0 [GDB will not be able to debug user-mode threads: /usr/lib/libthread_db.so: Undefined symbol "ps_pglobal_lookup"] GNU gdb 6.1.1 [FreeBSD] Copyright 2004