I found details of a bug in DPMI under certain versions of windows on Microsofts site:

SYMPTOMS

A Windows-based application that specifies "reset interrupt controller and A20 line" when calling the MS-DOS protected mode interrupt (DPMI) function "Simulate Real Mode Interrupt" can cause Windows to crash.


RESOLUTION

Applications that use the "Simulate Real Mode Interrupt" function must ensure that this bit is not set.

So, with this in mind, you could try adjusting the SimulateRMInt function by deleting the line shown below:

BOOL FAR PASCAL SimulateRM_Int (BYTE bIntNum, LPRMCS lpCallStruct)
	{
	BOOL fRetVal = FALSE;        // Assume failure
	_asm {
			push di
			mov  ax, 0x300         // DPMI Simulate Real Mode Int
			mov  bl, bIntNum       // Number of the interrupt to simulate
// REMOVE THIS LINE	mov  bh, 0x01          // Bit 0 = 1; all other bits must be 0
			xor  cx, cx            // No words to copy
			les  di, lpCallStruct
			int  0x31              // Call DPMI
			jc   END1              // CF set if error occurred
			mov  fRetVal, TRUE
		END1:
		  pop di
		  }

	return (fRetVal);
	}