Hi Franco,

Your WriteFile call looks Ok. So may be:

1) Check WriteFile declaration

DECLARE INTEGER WriteFile IN kernel32;
	INTEGER hFile, STRING lpBuffer, INTEGER nBt2Write,;
	INTEGER @lpBtWritten, INTEGER lpOverlapped

2) Call GetLastError to determine the error more accurately:

DECLARE INTEGER GetLastError IN kernel32
? GetLastError()

For example, it can be 5=ERROR_ACCESS_DENIED.