DVD error code

Hello,

I try to play a DVD disk on my computer and got the DVD error code 8901000F.

Circumtances when the error code appears :

Computer :
Mother board ASSUS P4S8X (bought in the US)
Pentium IV 2.4 GHz.
512 M DDR Ram

OS :
Win XP Pro US version.

Material :
One Pioneer 106S DVD drive bought in Europe (region 2) installed as master on the secondary IDE connector.
One Sony DRU-500A DVD burner bought in the US (region 1) installed as slave on the same IDE as the Pioneer.DVD Player :
PowerDVD4

Problem :
When I try to play a region 1 DVD with PowerDVD4 (bundled with the Sony drive) on the Sony drive I got the DVD error code 8901000F.
Region 2 DVDs will play fine on both drives althought the SONY is supposed tobe a RPC2 region 1 drive.

Could you help me please?

Thank you