Thanks for the reply. I figured out my issue. I didn't bother creating a custom URL, and the link with 'profiles' is the default. When I created a custom URL, my profile link changed to 'id' and the import worked fine. Sorry for the false alarm.
I'm a new LaunchBox user and am having the same problem importing from Steam. I did notice that the base URL for my profile is different than what is in the LaunchBox importer.
LaunchBox: http://steamcommunity/id/<user identifier>
Steam Profile: https://steamcommunity/profiles/<user identifier>
When I manually try these in my browser, I get an error with the LaunchBox version but not the other. I can't find a place in the options screen to edit the base part of the URL.