If you are using Lotus Traveler in a High Availability environment and upgrade to Traveler 8.5.3 Upgrade Pack 2, you need additional steps that is not documented.
After applying the UP2, you need to run 2 sql scripts to update you environment.
1) Unpack and switch to the DB directory in this case
2) Run the following commands to update database
db2cmd -c -w -i db2 -tvf fixpack5.sql
db2cmd -c -w -i db2 -tvf fixpack6.sql
3) Start Traveler