CMS Errors

When I try to use the combo box inside my content management system, ModX, i get the following javascript errors:

Message: ‘arguments.0.length’ is null or not an object
Line: 23
Char: 3
Code: 0
URI: codebase/dhtmlxcombo.js

However if I make an exact duplicate page and call it outside the content manager, it renders perfectly.

Any advice? Please help.

Such an error amy occur if you call addOption method without parameters. For example combo.addOption();

This method may take the array of options:
combo.addOption([[1,“one”],[2,“two”]]);
or
a single option combo.addOption(“1,one”);
as a parameter