Anyone know the maximum size of an app file?

Anyone know why 7.0 produces fatter indexes (CDX) than 6.0?

I've been struggling with error 1150, "Not enough memory for file map". I've been building this application that contains many big free tables for the last 8 years from version 2.6 up. No problem until this year. I tried limiting buffers with SYS(3050) with no effect. I eliminated terminal services, also no effect.

Here are the particulars:

The application includes files totalling 2.3GB. The largest table is 541MB (2.6 million rows) with a 1.3GB CDX file. Last year this CDX was only 563MB. I've only added a couple of new tags to the index (one or two character fields). Therefore, I asked, why is the 7.0 index so much larger?

Last year the resulting app file was 1.6GB. I assume if I could successfully build the app that it would be 2.3GB. Does that exceed a foxpro limit? The documentation doesn't mention anything about the maximum size of app files as far as I can see. However, the maximum table size is clearly documented at 2GB. Maybe this applies to any file?

Any help would be greatly appreciated. Thanks.