|Kind of hard to tell. We'd need to know the exact software name and version probably. That may not be enough. The exact file complaint might help us too.|
DOS programs could be simple to install or require some very odd things. One being special files and even locking on to various dos versions or command.com to operate. Setver command might work.
Also some files were left out of Vista for security I think. Might have to create an autoexec and config file.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10