I'm wondering why you are getting a VideoWave error when you are trying to burn in MyDVD...
First of all, you can try just importing the slideshow directly into MyDVD... though that depends entirely on how you created it. Slideshow assistant? Videowave? Please let me know.
If you created the slideshow in VideoWave entirely, you can try outputting your production. There should be a small film reel icon somewhere on the interface (I can't remember where right now, and I don't have EMC 9 in front of me.). Once you have a separate file, close videowave, and open MyDVD by going through the start path (Start->All Programs->Roxio EMC 9->Video->VideoWave).
Then try importing your VideoWave exported file into MyDVD, and try burning that.
If that fails, try a repair install. Start->Control Panel->Add/Remove Programs (On XP. On vista, it's Programs and Features). Then locate EMC 9 and click on "repair".
If that fails, a clean install might fix it, but please give us some feedback if it gets to this point.