You seem to have plugged a file into your transparency node, and I'm guessing it is that. If you look at the transparency on the image you have posted to the right of the transarency slider it show a black arrow instead of a checker. (That's what indicates the an image is plugged into it.) You need to unplug that image.
Ah, I see! Thank you!
Following on from Justin, to unplus an image right lick on the option (ie right click on the word transparency) and then choose 'break connection'
some maya ebooks free download http://bestmayabooks.blogspot.com/