Trouble with External DVD+-R/RW

Just puchased this (PX 708-UF2) I have installed the software it came with and now I am trying to burn a DVD. However when I get at the point of burning it does not list the DVD drive on a drop down window (can't find it ???) On this drop down it lists my CD-RW but even that is not highlighted so I can not change it. If I go to my computer, it lists the DVD burner there just fine (DVD-RW) I have it saved but not sure how to send an attachment on this....
On the instructions it asks that I have at least 6GB free on HD. I have about 7GB freed up.
Any idea anyone?



<SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">