>This client is trying to run a 1999 version of SBT Pro Series 5 on Windows 7 and gets error 1150 - memory error when trying to re-create indexes.
>I don't have the code and I don't have VFP 5 so I can't debug it.
>
>Any ideas?

no mention of 32 or 64 bit, nor phys memory, nor Home/Prof...

I'd try for XP mode on prof, or
play with the equivalent of XP's boot.ini /Maxmem setting
or a plain vanilla VM to skip the issue ;-))