Mbuild error code -1

All,

I get this message when using the compiler app on 2013b

Error: An error occurred while shelling out to mbuild (error code = -1). Unable to build executable.

What can I do to resolve the problem? I used the compiler app without any issues in the last month and today I absolutely cannot get it to work. What am I doing wrong? I've executed mbuild -setup and I moved MATLAB to first in my path.

I looked around the internet and some people said to just try building over and over until it works. I've tried many times without success. Any help is greatly appreciated.

[Harsheel]

This error may be caused due to corrupted environment variable "ComSpec". This variable should point to the command interpreter. From the windows dos prompt, what's the output of:

 echo %ComSpec%

It should be

C:\windows\system32\cmd.exe

[luca scarcia]

I've obtained from prompt the correct answer: "C:\windows\system32\cmd.exe". Have you any ideas to solve the error code?