If MTD is not printing on a Windows machine, the normal culprit is that it cannot find a valid license. Windows updates are well known for causing path errors. You may have to remove and reinstall MTD, reboot.
The last four MacOS are 64 bit only. 32 bit apps like MTD and Encore cannot work until upgraded. Encore 6 will be 64 bit and open older files but no one knows how old yet. Encore 5, unfortunately, could not open many older files.