There was a problem found with trying to install on a certain kernel version of Linux SUeS 11. This was fixed with the patch.
You will probably need to upgrade to DP 6.21 by installing the patch bundle, and then, at the very least, install the most recent Core and Cell Manager patches
The Patchbundle and individual patches are available at:
http://support.openview.hp.com/selfsolve/patches
You will be downloading the patches for your version of a UNIX-based Installation server