>Ed Rauh,
> Sorry i forgot to give the invoke statement it write in VB. Below is the Invoke statement in VB :
>
>> Out PortAddress, Signal
>> Inp(PortAddress)
>
>the first one will past two parameters to teh procedure in inpout32.DLL
>the second is get the return value from the procedure.
>
> i also want to ask about the inpout32.dll file, is it only put it in the windows\system directory ?

I would assume so; I don't know anything about the .DLL. If it's in the Windows\System (or under NT WinNT\System32 directory), or in the Windows directory, or in the directory where the application was first started, or in the current directory (the standard Windows search order applies) it should be found. Unless it makes use of registry entries for itself, it would not need to be registered; if it did need to be registered, you would od that with REGSVR32. The error you listed was caused by a misspecification of either the name of the .DLL or the exact, case-sensitive name of the entrypoint.