i can't to set keyframe
i don't know what happened with program.
when i click to set keyframe
it has show a yellow line that

// Warning: file: /Applications/Autodesk/maya2013/Maya.app/Contents/scripts/others/doSetKeyframeArgList.mel line 641: Current manipulator and active objects have no keyable attributes, , or animation layers are present and the BaseAnimation bar is not selected or locked.


Somebody help me? I'm a beginner of this program. I have Maya 2013 on Mac


Thaks.