I run on Vista.I figure most of my problems are VISTA related like game quitting to an error log.Only one time i got some popup after the game exited that looked like it was a feedback log from wizards,but it may have just been a microsoft feedback log.Anyhow i sent it in,to where ever it went microsoft or kingsisle.
Other than the few game exits,it runs pretty good with not many problems. If you can not even start the game,then it sounds like your typical driver problems.Usually the sound files are the first to load up,so perhaps your sound driver or as usual your video driver is no good.Try an updated video driver first.Do be careful,most sound cards are built in and you can't just guess or use any sound driver.If you have an after market card like a sound blaster,then yes it may very well be the problem with vista,as they NEVER had a proper working driver last i checked about 5 months ago.
We used to have an issue that was solved by right-clicking the Play Wizard101 icon and selecting Run As Administrator, but I believe this problem is now solved. If your original download is old you may want to reinstall once and that should solve it forever.
This may not be your problem, so post again if you're still having problems.