I just installed a new insteon dimmer switch and am having the same issues as leonpc. Everything worked fine prior to starting the "start linking" button. Now, "linking" window loops continuously and other commands generate "discovering nodes, retry" error window.
Saw reference to polyglot but don't know what that is. rebooting, restarting ISY994i don't help. Versions are
v5.0.15a both UI and Firmware. Not updated recently.