I think you have the ADS (not the ADSE) board. Mine has already a Sticker "Linux OS Rev. 7.1" on the CPU board, wich is Kernel 2.4 based.
I also downloaded Rev 7.2 (that also has a Kernel 2.4). I noticed that there is some progress in the official 2.6 Kernel regarding support of the i.MX21, but I think ist far from complete.
Are you working with LTIB? That should generate a quite stable kernel (if you stay away from USB and SDCARD support).
Christian