error with "imrotate" function

The matlab version I am using now is MATLAB 2009a. The function 'imrotate' worked perfectly previous, but I got some error when I was doing the same function to rotate a image matrix in different computer.

??? Undefined function or method 'imrotate' for input arguments of type 'double'.

Error in ==> Untitled2 at 12 Irotateref = imrotate(Iref,-0.4655179,'bilinear','crop');

So what's happened? Do I need to adjust something?

Answer 1

[the cyclist]

That error message indicates that the command is not found. Does the other computer have the Image Processing Toolbox? What do you get you type

>> which imrotate

at the command prompt?