Same thing happened to me.  I upgraded my VSS using ISSU eSFU with 12.2(33)SXI4 to 4a and encountered the same messages.  As soon as issu loadversion was issued, the script kicked in and attempted to reload the standby.  Except the standby never come...

Here is a sample config:!conf t!username admin password role network-adminusername admin password role network-operatorsnmp-server community [SNMP_COMMUNITY] roswitchname [HOSTNAME]ssh key dsa 768 forcessh server enablesystem default switchport shu...

I'm not sure what ios rev you're running but there is a memory corruption issue with 12.2(33)SXI3 - bugid CSCtb34857 - crashed seen in xdr_reference.