I don't know what kind of error you are getting but I was able to install MOHPA without a patch. I kept getting an error that it was looking for the next disc during the installation, even while the correct disk was in the drive. I will tell you what worked for me. I copied disk 2, 3 and 4 to the hard drive. When it asked for the next disk, I pointed to the HD locations and it installed perfectly. By the way, I finished the entire game of MOHPA in Windows 7 (64-bit) without problems. I hope this helps.