Can't post to Words with Friends

[lbeck]

Newbie and playing free version. I'm in the middle of a game and no longer see the icon (something like "play") to post a new word to my opponent. Is this because I'm using the free version or maybe because I made too many guesses at illegitimate words? I can't find rules for the game.

I do have the "surrender" flag available and I may need to use that but if it's just because I'm doing something wrong I'd like to get back into the game.