You can use a few tags such as the ones for bold and italics. You can't use most others. What I meant was that if you are getting a banned html error, you should look to see where you used those symbols because the error is likely to be related to your usage of them.

If you still can't figure it out, email the post to the webmaster address, I'll make sure to look at it and figure out what is wrong and see if there is any way to fix that.