Hi j,
sorry to say: ... zillions of options, what went wrong...
so, to locate the problem:
* where does the raw material come from? video but no audio is a "traditional" error; iMovie is for editing miniDV tapes, not "import from digi-still cam/some iNet download". esp. these "still-cam can do movies" movies are mostly "mpegs"; that is a file format, your Mac can play, but not edit... needs conversion... =>
* you're able to play project IN iMovie? with sound? no audio here? => conversion
* iMovie plays video+audio; choose "share"/Quicktime/Fully Quality"; creates file of ~500MB; open that with QTplayer - ok?
* drag'n drop that into open iDVD project... =>done
* Movie had no sound/conversion; download/use for free STREAMCLIP:
http://www.squared5.com/; convert mpeg to dv; drag that into iM; continue usual workflow
* still no go? what Mac? how much FREE disk space on internal drive? iDVD needs at least 10 - 15 GB of free disk space to work properly....
* do you use any purchased music from the iTunes Music Store? depending on your version of iM/iDVD (tell us) needs "conversion" (iLife6: not needed, any version before does need a legal workaround)...
.....