[GENERAL] WARNING: some databases have not been vacuumed in 1953945422 transactions

[MG]

Hello,

we are using PostgreSQL 8.0.3 and have two databases in one cluster. db1 and 
db2.
Each night a shell script is being executed.

vacuumdb --analyze -U cmduser db1
vacuumdb --analyze -U cmduser db2

The last weeks the following warnings are given out:
WARNING:  some databases have not been vacuumed in 1953945422 transactions
HINT:  Better vacuum them within 193538225 transactions, or you may have a 
wraparound failure.

Now I made the sql-statement:
SELECT datname, age(datfrozenxid) FROM pg_database;

 Yesterday I got this result: 
      datname  age  
      db1 1.090.080.531 
      db2 1.940.858.511 
      template1 1.940.858.511 
      template0 1.940.858.511 


Today I got the following result:
 datname age 
      db1 1.075.558.667 
      db2 1.075.513.031 
      template1 1.955.716.521 
      template0 1.955.716.521 


Why are there changes of the databases template1 and template0 ?!?

Is this critical?

Regards
Michaela