I am sorry to say it, but I think that you are going down the wrong path here.

First of all, you have the usual problems with maintaining flatfiles. Next you need to access files on the correct machine. Then you need to handle locking, (which few people get wrong). Then you need to maintain this as it grows.

It is a big pill to swallow, but personally I think it would be a mistake to go farther down this path. Instead I would suggest rewriting the whole thing to use a relational database.