Questions about Save button

Hello,

I have added FCKEditor to my .Net web site but I have problems to implement the save button.
Effectively, when i push on the Save button i have this error: 'null' is null or not an object.
For the moment I use the default toolbar.

My second question is how can I implement the FCKeditor_OnComplete property whith javascript or better directly in a .Net event.

Thanks in advance

Ben