Invalid history version in header
I kept getting this error and was filling my db2diag.log. A little bit of research revealed it was because a bug in the health monitor code was corrupting the SYSTOOLS.HMON_ATM_INFO table. The quick fix for this is to drop the  table, the table will be recreated next time when the autonomic feature starts up. Below is the error message :
2009-05-23-15.11.39.865000+120 I1463721H438 * * * LEVEL: Severe PID * * : 3986 * * * * * * * * TID *: 4332 * * * *PROC : db2fmp.exe INSTANCE: DB2 * * * * * * * * *NODE : 000 APPID * : *LOCAL.DB2.081024721124 EDUID * : 4332 FUNCTION: DB2 UDB, Health Monitor, sqlmhMonCollHistReadHeader, probe:20 MESSAGE :Invalid history version in *header DATA #1 : Hexdump, 4 bytes
Here is the link from IBM that describes the bug and the fix :