That's in AS3, in AS2, it's the frame number first and then the scene name (string.)
Because you only put one argument, Flash assumes that's the frame label because the gotoAndPlay function's scene name parameter is optional, but the frame number - or label - is required.
Also Jesse, I've had some problems getting scenes to work efficiently in AS2, they're a tad unreliable. Since then, I've switched to using frame labels in the same scene. It works just as good, and uses less bandwidth.