If you are using the HBDotNet code that was written by a couple of HouseBot users, you will need to update the HBDotNet DLLs or HouseBot will crash on startup when loading the Devices.
You can download the new compatible versions here. Just copy them over the old DLLs.
I've never created anything with this, but here are the basic instructions:
1) Copy HBDotNetBridge.dll into the \housebot\plugins\devices folder
2) Copy HBDotNet.dll into the \housebot folder (!)
3) Create a new C# class library and add a reference to HBDotNet
4) Derive a class from HBDeviceBase (applying the proper attributes)
5) Build your project and put the resulting dll in \housebot\plugins\devices