Error, Incorrect XML in Drupal

Hi, I recently found this awesome calendar after searching for hours one application with all this characteristics.
I’m using the Drupal Module in Drupal 6.19. After activating the module i can use the calendar with’ but the error type LoadXML, description: incorrect XML appears.
The events dissappear after refreshing and aren’t saving in the databse.
After reading and searching the forum I can’t solve the problem. Also I don’t know how to enable debug mode from drupal because in settings of dhtmlx scheduler the option does not appear.
Can somebody help me with this issue???

Unfortunately the further development and support of Drupal plugin was stopped.

As for your error - be sure that you are loading the page and browser, by using the same domain name as in Drupal’s configuration ( due to cross-domain security, calendar can work only from the same domain as specified in configuration, loading from any other will result in “incorrect xml” error.