I see. I've always thought Windows was getting kludgy. This kind of supports that idea. Port-to-port communications within the same PC should be a lot simpler, one would think.
I am also getting this error when trying to link FMP24 to DSD+. FMP24 says listening... so I start DSD+ and i get multiple connection attempts with error TCP link version error and 10053, then DSD quits. I am using DSD+ FastLane v 2.39. I have authorized the link via firewall, and disabled the firewall.