Richard, here's a suggestion (though it is more work). Type your post in Word or whatever word processing program you use and run it through the program's spell checker. Then, cut and paste it onto the forum. That's a good work around for not having a spell checker.
We got an email from the owners of Spellchecker that stated that since they are not getting the advertising revenue from the banners that they put in the pop up window that they were going to start charging on a per use basis. You have it on your own server but that costs several thousand.
I guess that since you are on their site using it it wouldn't cost them anything. It is just remote users that they have begun to charge.