The boards will display it but Netsacpe will not. If it causes problems (like it has been) we ask you to remove it until you can straighten it out OUTSIDE of your signature first.
With the old boards this wasn't so much of a problem but on the new boards ALL of your posts are affected by the bad code, locking them all up.
In this case I think that you just forgot to close the IFrame but, I was trying to get the code out ASAP, thus my short tone.
Go ahead and try it here outside of your sig and we will see if it works the way you want it to.