You need to convert it,
To convert is u can download Moyea FLV to Video Converter Pro: The one i ever used, or you can get other freeware video format converters.
Once you use the converters: BEST TO convert them to AVI.XVID or AVI. DIVx, Note. Mpeg-4,3.etc wont work on your dvd player.
If you want to Convert a DivX or XviD AVI to DVD
go to this link,http://www.afterdawn.com/guides/archive/convert_avi_to_dvd.cfm
It will still work on your dvd player if you dont convert XviD AVI to DVD .
Once finished converting you may watch and enjoy it on your dvd player..
DISADVANTAGES for MOYEA FLV to VIdeo Converter Pro: It is a trial version so when u convert it there will be a watermark on the top of ur video. If you dont want the watermark on your videos when converted, u can download other freeware video format converters, just google it and many will come up. Lastly, i hope i helped you.