Thanks, I've been looking up and down the www and couldn't find anything. However, your idea did the trick. This is what worked in my Vista. Like you said: Go to Windows Movie Maker and load the audio file in question to the movie timeline. Then, I "published" the movie to "this computer" and gave it a name, location to save into and clicked Next. On the next screen, I chose "Best quality" settings and clicked "Publish". I ended up with a 156 kbps Windows Media Audio file that Pinnacle accepted and played nicely.
Of course, this method adds more steps to the process, but for my purposes, it beats having to download and install additional software in my computer.
You've been very helpful. 