USB 2.0 conflict with ADS drive kit and HP external dvd burner

I just purchased an ADS dual link drive kit (usb & firewire connectors). I
have found that I cannot have this drive kit plugged in at the same time as
my hp 300e dvd writer if both are using usb 2.0connections. Doesn't seem to
matter which usb port I use (my Intel MB has 6 ports). If I unplug the
dvd, the ADS drive works fine when I attach it. If the dvd is plugged in
first and then the dual drive is plugged in, XP says the usb device is not
recognized for the drive kit.
If I plug the ADS drive in by itself, it works ok. If the dvd is plugged in
second, then I get delayed write failures accessing the hard drive in the
ADS drive kit. If I plug the ADS into a usb 1.0 hub, it seems ok too except
for the low speed warning (plugging 2.0 device into 1.0 usb port). Any ideas
how to have both working on usb2.0?

The drive in the ADS case is a Western Digital 180G, 8M Special Edition
drive.

HP says no problem on their side since the dvd writer works ok.
--
Phil Tomaskovic
Please remove NOSPAM from email return address.