It's a few years since I installed one of these myself, but isn't it the case that the utility and WL itself cannot both access the serial port at the same time. Also, I don't know which version of WL you have installed but it looks like it might be reasonably old one - might be worth updating (this won't solve the sharing collision but it's obviously good to be using the latest version).
So I'd suggest a couple of things:
1. Have a look at the streaming logger text file that explains how to configure the logger;
2. Close WL before trying again to use the utility.