Foxpro RUNning Pascal - problem in sharing files - HELP!

I have a Foxpro (2.6 for Windows) application which interacts with the user,
and then shells out to a Pascal (BP 7.0 for Windows) program to do
processing.

Here's the Foxpro part:
  USE MYFILE.DBF
  ...  && do some stuff
  USE  && (or CLOSE DATA) to free it for the next Pascal program
  RUN /N MYPASCAL   && calls Pascal
Here's the Pascal part:
  VAR
    MYDBF: file;  { untyped }
    BUF: string;
  BEGIN
    ASSIGN (MYDBF, 'MYFILE.DBF'); {actually I pass the name as PARAMSTR(1) }
    RESET (MYDBF, 1);
    BLOCKREAD (MYDBF, BUF[1], 100);  
    etc. { routines to process a DBF table }
Usually this works fine. It worked when both programs were DOS-based
(Foxpro 2.6 and BP 7.0 for DOS). It also works when Foxpro 2.6 Windows
calls BP 7.0 DOS. (Both programs are cross-platform, using compile-time
directives like {$IFDEF WINDOWS)).
  This method also works when both programs are Windows-based, at least with test
code like the above. However, the real applications do NOT work any more.
  When RESET is tried, I get Runtime error 005 at 0001:CEF5. If I use
IORESULT, the result is 5. The file cannot be opened, and
BLOCKREAD fails with error 103.
  I have examined the situation thoroughly, and I am sure MYFILE.DBF
is closed before the Pascal program is called. And yet, for some reason,
the Pascal program acts as if the Foxpro program is not releasing it.
  I can't even think of a workaround.
  HELP!!!