Dual Boot Vista/XP - problem installing XP

Hi,
I'm trying to make a dual boot system Vista/XP with my HP Media Center purchased in 2007 with Vista pre-installed.
Inside Vista I created the partition for XP (disk D  and rebooted with the 'XP Pro SP2' (2004 CD) inside.
After selecting its correct partition for installing it copies all files on hard disk and it reboots in order to start its installation.
Unfortunately at this point, upon rebooting and starting first time from hard disk, it says that there is an error in the system and stops.
If I install only XP on the system it works correctly even though some newest hardware is not recognized.
I had already made a dual boot two years ago with a 2007 XP Student Edition and it smoothly.
Does anybody know if it is due to the XP version being too old (2004 CD) that maybe cannot deal with the boot record created by Vista?
Or perhaps such an old XP cannot recognize a boot hard disk that is not C:?
Is there a way to bypass this point (perhaps fixing the boot record) in order to continue correctly the installation?
Thank you,
Al