WYSIWYG-editor problems with Burnt

I use the Burnt theme with Drupal 5.2 and it works quite good.
I use another theme for the admin section though.

But I have a problem, I can't get TinyMCE or FCKeditor to work with the Burnt theme.
Well, maybe not so strange because it is made for Drupal 4.7

FCKeditor:
Nothing happens when I click on "Open rich editor" in Firefox, IE says:
Line: 111
Char: 1
Error: Object expected
Code: 0

When I try to use TinyMCE instead I get this error message in Firefox with Firebug when clicking on "enable rich-text":

mceToggle is not defined
javascript:mceToggle('edit-body', 'wysiwyg4body');
Line 1

I can't find any *.js file in the source code.

Any solution how to fix this?
I prefer that TinyMCE should work.
Hopefully there will be an 5.x port someday!