Applications works fine on Windows NT/200 but not on Windows 98/95

Hello,

I am trying to run a Visual Basic application on Windows 98/95. It doesn't report any problem / error, but the application does not work. The same application works fine on Windows NT/2000.

The application uses a C Dll and accesses a Control Unit through the Serial Ports ( COM 1/2/3/4). I noticed that while running the application on 98, it fails to communicate successfully with the Control Unit through the serial port. This results in the failure of the application. Can anyone help in finding out the possible reason for the application not working ?

Some more information on the application :
I haven't used named pipes in the Visual Basic Application. The VB application uses a C DLL which communicates with the Control Unit through a Serial Port. (Function CreateFile() is used to create handle to COM port, SetUpComm() used to initialize communication parameters, SetCommState()/GetCommState() used to write/read DCB structure, GetCommTimeouts()/SetCommTimeouts() to get/set timeout parameters,ClearCommError() to clear communication errors, ReadFile() to read data from COM port, TransmitCommChar() to transmit char through COM port and CloseHandle() to free handle). Are any of these functions incompatible with Windows 95/98 ?

Thanks,
Rad