Error when playing sound in Matlab Version: 8.1.0.604 (R2013a)

Recently (July 22, 2014) matlab stopped playing sounds and gives an error. My computer is a Lenovo T420s, Win 7, Matlab MATLAB Version: 8.1.0.604 (R2013a),

From the command line:

load gong.mat
sound(y,Fs)

gives the error message:

Error using sound (line 76)
Undefined variable "internal" or class "internal.Callback.validate".

The system sounds are working normally; it is just the matlab sound command that is producing errors.

I get the same error when using:

player = audioplayer(y,Fs);
play player

Undefined variable "internal" or class "internal.Callback.execute".

Error in audioplayer/resume (line 745)
            internal.Callback.execute(obj.StartFcn, obj);

Error in audioplayer/play (line 102)
obj.resume();

Any suggestions would be appreciated.

C Hopkins

[Star Strider]

Submit a Support Request to TMW. It seems something only they can solve.