Marvan, there are so many ways on how DLL's and hardware work together. I managed to hook up my hardware by reading the DLL documentation and adapting the IO data types to the Call Library function vi. Here the NI documentation (helpfile and whitepaper on DLL) helped a lot.
My code doen't help you because to run the vi you need the DLL and to run the DLL you need the HW. However if you can't come along, post your vi and the .lib file of your DLL (I don't really want to upload unknown DLL's on my system)
IN
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'