My guess is that you have used var1 as a different data type before executing this code. I am able to copy and paste this into my MATLAB command window and run without error. I suggest changing "var1" to a different variable name or use the command "clearvars" (as seen in this documentation page: http://www.mathworks.com/help/matlab/ref/clearvars.html ). Make sure you are using the same variable name for consistent data types. I hope this helps.
Ryan