Hi savage,
Yes, we do test it on Windows XP and Vista as well as Linux (Ubuntu 8.04). We use XAMPP for this purpose, which bundles Apache 2.2, PHP 5 and MySQL 5. The only big difference in versions with what you have is in Apache (2.0 vs 2.2), but I doubt that could be the cause.
If you happen to find the cause please let us know so that we fix it for 1.0.
Thanks.