Audio problem in PowerDVD & 5.1

[spooky]

I am wondering if anyone else has noticed this problem too, I just got myself some new speakers, Logitech 5.1 Z-640
so I decided to try them out with some of my DVDs, well everything sounds great except for one thing, I am missing the center channel audio so that means I can not hear anyone talk at all.
This only happens when I use PowerDVD or WinDVD, when I play the dvd using media player I get the audio no problem.
here are my hardwares I have:
Turtle Beach Santa Cruize sound card
Logitech z-640 speakers
Toshiba DVD player ( not using the s/pdif cable )
Soyo board with XP2400
512MB Crucial memory
TI4600 128 MB video card, Xtasy, Visiontek

Could someone give me some suggestion?
By the way I have tried many movies
Thank you

[vance43211]

i had that problem last year

it seems that i had the center and subwoofer lines switched

[spooky]

Vance,
where would I switch the wires? There are three wires coming off the Logitech speakers, one is the rear, one is the front & the orange one is for sub & center speaker.