Firstly, make sure that the file you are trying to open isn't already opened in another application. I know this is low chance to happen, but check it just to be sure. Secondly, if the file was produced with another version of the software, then you might face some compatibility issues between older and newer versions of the Image-Pro Analyzer. This might be the case where your colleague had the chance of opening it.
And, of course, the file might have its headers corrupted making it impossible to open it. Obtain or download another version of the file one more time and then load it up.