"Not a valid CySmart Dongle!" error CySmart API

I am trying to use the CY5670 CySmart USB dongle with a C# program using the CySmart APIs. I found example code for connecting to the dongle, but every time I try to connect I get an error--"Not a valid CySmart Dongle!" I have made sure the firmware is up to date, and the dongle works fine with the CySmart software. What could be the problem here?

I've attached my code and the DLLs I'm using.

Thank you.