Your in for alot of hurt.
We did this +- year and half ago and I am still in pain.
We set it up on a SLES 8 box which according to IBM was not supported at the time, but it worked.
Look at :
http://www.ibiblio.org/pub/Linux/doc.../DB2-HOWTO.pdf
There is a part in it to get it working on the 2.4 kernel.
Although it is for version 7.1 I do not think 7.2 will differ much.
Oh and getting the command centre gui working is another basket of rotten apples.
Why not use mysql ?
Word.