I get this when I go to render then change material.
createAndAssignShader blinn "";
connectAttr -f blinn19.outColor blinn19SG.surfaceShader;
// Result: Connected blinn19.outColor to blinn19SG.surfaceShader. //
// Error: file: /Applications/Autodesk/maya2013/Maya.app/Contents/scripts/startup/createAndAssignShader.mel line 153: No renderable object is selected for assignment //
// Created shader blinn and assigned to the selected objects. //
// Error: file: /Applications/Autodesk/maya2013/Maya.app/Contents/scripts/others/updateAE.mel line 504: Cannot find procedure "AEsetDisplayToEmpty". //
// Error: file: /Applications/Autodesk/maya2013/Maya.app/Contents/scripts/others/updateAE.mel line 527: Cannot find procedure "AEsetDisplayToNodes". //
I'm using a MacBook Pro.