Hardware – DVD Burner connected to onboard SATA vs PCI Express SATA ?

I have an ASUS M2nPV-MX board. This board had 4 SATA ports onboard. I bought a PCI Expres SATA controller as I needed more SATA ports. The Controller is this one:
http://cgi.ebay.com/4-Port-SATA-SERIAL-ATA-IDE-PCI-CONTROLLER-RAID-I-O-CARD-/350444316016?pt=LH_DefaultDomain_0&hash=item51981be570

When I plug my DVD optical drive on the onboard SATA it plays DVD and I am able to burn also. When I plug the DVD optical drive on to the PCI Express card, I am able to play DVD s but not able to burn.

My system has two DVD drives and the same result with both of them when , when I plug into PCI express card – cant burn , when I plu into onboard SATA – able to burn.