Hi,
The dll has not been updated and unlikely to be. Something in Mach3 has changed to cause it not to work, and I am not the author so do not maintain it.
The manual has not been updated for a while as the functionality has not changed.
That said, things in Mach3 have moved on somewhat with the brains functionality that Art wrote. You can set up the communications to each of the ModIOs in the new Serial Plugin config screen. Then use the Brains to interface to each of the ModIOs
As to wiring for RS485, which is needed for multiple ModIOs, they are wired as detailed below.