A Notice to Dodson’s ProHEC1 and ProHEC2 Users:  

As of 7/1/2003, Dodson will no longer provide support for ProHEC1 and ProHEC2. These DOS programs have been replaced by our HydroPro for Windows program and is included with our ProHEC-CD package.  

Problems when running DOS based programs in Windows

Important: Solution for running DOS programs with current operating systems and PC's: 

http://en.wikipedia.org/wiki/DOSBox