What dvd format will play in 867 MHz with a MATSHITA CD-RW CW-8121 drive?

The answer to your question has several factors that are included in the answer.
http://docs.info.apple.com/article.html?artnum=25402
Read through the above link, and this will give you a broad outline.
The main thing to remember is with older Drives, Slow is best 1X or 2X speed.
If a windows machine is doing the burning the software settings must be Mac and PC compatible. There are settings on most major softwares.
http://docs.info.apple.com/article.html?artnum=303599
Use High Quality Media. Mac is more particular about media then PC's
http://www.digitalfaq.com/media/dvdmedia.htm
Lastly regular Audio, Data, and Video that are standard Formats are not a problem generally However,Many file formats that are generated by windows based machines can and are problematic. WORD files for instance. Unless you have Virtual PC and one of the Microsoft Softwares for mac.
Do your home work and be specific as to what you are copying,
The General Information you need is on the links provided. Be sure you use
DVD-R Media. Read the packaging on the media you buy make sure that it will burn 1x,2X,4X,8X and 16X.
Don