Mitsy Point of Sale Program

I was just asked to solve a problem involving the Mitsy Point of Sale program. This is a 4gl running on Informix 2.10. The client has only the 4ges and some error logs. The problem I was asked to look into was that Balance values (for account receivables) are not being calculated. The error logs indicate error 284, subquery returning more than one row. And possibly some other problems. Anyway, as is fairly obvious, tracking exactly which table is off will be very time consuming. Consequently, I'm hoping someone who reads this list is familiar with the Mitsy program. The opening screen indicates it comes from a company called Positek, Inc. but I'm told it was sold to Compudyne. I'm also told there are 100 or so users of this package that have now been left unsupported. If anyone can help me track down the source code or at least someone familiar with the program, I would be grateful - and the owners of the small photoshop involved will be ecstatic. Thanks, Scott H.