Well when you have over 50 forums it is pretty hard even with a adequate amount of RAM to fully load that Edit Forums page-if you have more then one window open on the board it usually will not load the Edit Forums page. Is that where you went to add the new forum? It seemed like you said you used the Add Forum button, correct? If so then you might have a 'Default Forum Settings' set up and that might be why it didn't seem like it had the right settings and that you had to delete them. If you need one deleted because it won't let you then link it here and BbBoy can remove it for you.
About the other thing with posting and the posticons-does this only happen in New Thread screens? Or was this just a one time occurance? If it seems to be following some type of pattern maybe you can help us find out why it is happening. The drop down select menu you saw there, what was it for? Was it for Fill Text or a Custom Field?