In my experiences with DB2 (and other IBM products like Websphere Studio, Lotus Domino), I have had to set the LD_ASSUME_KERNEL enviromental variable because there seems to be a problem with the install shield that comes with these products. I'm running on Suse 9.0 with a 2.4 .x kernel with DB2 v8.1 and WS Studio 5.1.
You could try
$ export LD_ASSUME_KERNEL=2.4.21
. There are however some implications of doing so (explanations of which I did not manage to fully understand).
In most cases this only need to be set during installation, except in some cases your DB2 control center might give you the same problem.