Opening an mex file

I tried to open an mex file in Matlab. The mex file has the same version as that of the current platform. I verified it by >>mex = mexext and it returned mexw32. The file I am trying to open also has the extension mexw32. But when I tried to open, some unreadable text appeared, with the indication 'This program cannot be run in DOS mode.' Please let me know what does this mean and how can I resolve this problem. Thanks a lot in advance.

[Walter Roberson]

What actions did you use to try to "open" it?