If you have problems with the encoding then please set force charset to “utf-8” or define a working language in your user/group typoscript configuration.

The calendar doesn't work in the palette if you use PHP4 and TYPO3 3.8.x. Please enable “Show secondary options (palettes)” to prevent this problem. You can use the date2cal configuration option “secOptionsAlwaysOn” to do this automatically.

If you get error messages like "too much recursions" or "stack overflow", you are using PHP4. The extension doesn't work with PHP versions below 5.x since the 7.x branch.