I have a command button in a spreadsheet, which when clicked attempts to call a procedure (ADC1632.dll) which communicates with a port, but the button only works if i open excel.exe then go File>Open and point to the path.

I want to be able to just click the file and the ADC1632.dll file is found and works fine??, but currently it comes up with the Run time error 53, file not found and it is the line
ok = adc16_open_unit(Port)
that is causing the problem, as its the open statement that is not communicating.

Do you have to declare the open or something?

Thanks in Advance