Undefined function 'de2bi' for input arguments of type 'double'

This tool is used in some third party matlab code to convert decimal to binary. When the code is run under MatLab 2009 (32-bit). The code works fine and no error is reported. However, running the same code under MatLab 2013 (64-bit) reports the above error. Both versions of the matlab are run on a 64-bit machine. The ver indicates communication toolbox is installed. Paths for all tools are properly set in MatLab.

Can someone suggest why the code reports error under a 64-bit Matlab but not under 32-bit?

Thanks, Zahid