I’ve done a bunch of testing over the last week around this error, installing different fixpacks and versions of DB2 on Ubuntu.
To recap, this error happens because DB2 can’t understand the more modern and secure sha512 password cipher and must use the older md5 cipher . About 6 months ago I wrote a post about how to workaround the problem on Ubuntu and other modern Linux distributions.
To make a long story short, this problem goes away with DB2 9.5 fixpack 5 , and DB2 9.7 . It is still present in DB2 9.1 fixpack 9, which is the most recent version of the DB2 9.1 series at the moment, so you will need to perform the steps in the linked post above if you need to be on this version. Otherwise, it would be much simpler and more secure to go to the latest fixpack of 9.5 or 9.7.