Oh boy, that game again. It's one of my favourites!
1. Take your .mer file and put it on a 32 bit machine that has FTView Studio installed (I can vouch for this working using v7; not sure about other versions)
2. Use the Application Mangler...sorry, Application Manager to "Restore Runtime Application". Select your .mer file and give it a name
3. Open FTView Studio and select the file you just restored. It will warn you that it's about to do a conversion. Let it do so
4. Once it finishes the conversion, close FTView Studio and re-open your Application Mangl...Application Manager
5. Select "Back Up Application". Back up the application to your hard drive. Hey presto, you now have an .apa file
6. Copy that .apa back to the machine you want to work with it on. You can now use the Application Manglager to restore it into your FTView Studio, edit it, and create new runtime files
7. Profit!