- Check if your theme is compatible with WP 3.3. To check, you may try switching to the default theme (twentyeleven) for a moment by renaming your current theme’s folder in wp-content/themes. The idea is to force WordPress to fall back to the default theme to rule out any theme-specific issue.
-also, make sure all your plugins are uptodate and compatible with the 3.3. deactivating ALL plugins temporarily to narrow down the problem. If the problem goes away, activate them individually (one-by-one) to find the problematic plugin.
-Ipstenu has put togather an extensive 3.3 troubleshooting guide. Please review it as well.