ZC is not fully supported on Vista at this time. Although many users have had no problems getting ZC to run on Vista, here are a few things to try if ZC crashes on start-up:
1. Use the ZCLauncher to start ZC in full-screen mode. In many cases ZC will no longer crash if started through the Launcher.
2. If the above doesn't help, run ZC in windowed mode (use the -windowed command-line parameter).