Sorry to dig up this old thread, but I feel like getting clarification on this would also benefit future visitors who found this through a search engine like I did.
How about opening up a new post with your issue then? Also having a syntactical correct sample (yes, what you wrote is right) does not help to check your specific case. A “real” sample that throws the also completely posted error is the least you should add.
My guess into the black-box you hand us is, that you probably lost count of opening and closing brackets somewhere along the line.