The reason you are receiving this error is because the PHP interprator thinks that anything starting with "<?", i.e., "<?xml" is actually php code, which in this case is not true.
What you must do is to set the short_open_tag to off in your php.ini file.
This will then force php to only recognize the "<?php ?>" or "script language=php></script>" style tags.
Kind regards,
Kelvin
[EDIT] ClausVB: deleted (ugly) german translation