Reading what is going on, I actually am wondering if there may be multiple versions of the SDM sitting on your machine.
1) Take a look at add/remove programs. How many instances of a program called Device Manager are listed?
2) When you use just the utility, could you double click the SDM icon in the bottom right and copy the text that is displayed after the utility startsup? It may be helpful to see what is going on. Also copy the text when houselinc is used, then open the utility.
3) This may be a bit much to propose, but have you tried cleaning your machine of houselinc, utilities, and all device managers? Then, install houselinc and then the utility. This ensures a clean SDM / driver / app setup.
FYI: The utilities all use isresponding to see if the PLC is there and ready to go. We also try multiple instances of a connection. Also, all new versions of the utilities now use the same communication “backbone”.