RH> only difference is that they defined the userid 
 RH> parameter as unsigned char far, and this didn't seem 
 RH> to work with C/Set++, so I used UCHAR.  Has anyone

Try sticking APIENTRY16 in the prototype of any ES 1.0 function you call. 
This will take care of everything,  except pointers to pointers,which will
require a _Far16.

APIENTRY16 is defined in the 32bit os2def.h as:

    #define APIENTRY16  _Far16 _Pascal

--- Maximus/2 2.01