Too many errors with html code in fckeditor

Hi, im using fckeditor R2, and one of my first problem was with '@', if something like <user@domain> come in the HTML when i want to send in my form a javascript error ocurr.

Another is with the COMMENT in the HTML...

etc.. there is a global solution to fix this? or i need to parse my html to eliminate again and again the posible bad code?

or.. somthing wrong in my configurations?

Well.. i need some help for this...

Thanks....