I had the same problem. The var's have to be declared before you include the
htmlarea.js file. If you were placing them in the JS Header (like I was) and
then referencing htmlarea.js in the HTML Head Content they are in the wrong
order. I just cut and paste the $$HTMLHead from Jake's sample database.
Another gotcha I ran into...
Your rich text field needs the Id set to the field name (see html tab on field
properties in demo database) or you will get an error about offsetWidth is null.
Thanks for all your hard work, but one suggestion. It would be nice if your
demo databases included a bare minimum working form w/o all the codestore look
and feel. This would make it easier to move into another application.