lcjoyinfo=replicate([ ],4)

The above statement allocates only 4 bytes, which is not sufficient for the JOYINFO structure:

typedef struct {
  UINT wXpos;
  UINT wYpos;
  UINT wZpos;
  UINT wButtons;
} JOYINFO;

Since the structure consists of four 4-byte unsigned integers, the statement should change to

lcjoyinfo = REPLICATE(CHR(0), 16)

Generally CHR(0) is a cleaner way of populating the buffer rather than stuffing it with the spaces (CHR(32)). For this API call this is probably not important, but for many others it is.