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If your file name has an .ach extension then it is a PLC5 application and will require RSLogix 5 software; this is pretty pricey nowadays ($9500.00 List); I don't think I have a RSL5 VM anymore, however, some of the members might be able to help you.
Try to archive (zip) the file and attach it to a post again.
The only way to download any Rockwell software is by owning a TechConnect contract; all their products will run for 7 days without an activation so if you have an old install disk try running it and use RSL5 for 7 days.