audioread function error with undefined variable

I am trying to get this to run:

[y,Fs] = audioread('cap1.mp3');
sound(y,Fs);

Yesterday it was working perfectly. Today it is erroring out in audioread function and saying:

Undefined function or variable 'nel'.

Error in audioread (line 134)
        throw(exception);

Error in taunts (line 15)
[y,Fs] = audioread('cap1.mp3');

Anyone have any ideas as to why this could be? oh and I am on version R2016a. But it works just fine on another computer running R2016a.

[Walter Roberson]

I speculate that somewhere in audioread you have accidentally changed a reference to channel to be nel or possibly chan nel. You should

edit audioread

and search for occurrences of nel that are not channel and change the context to be channel