Don't see any errors there. It looks like possibly it worked but didn't find anything that matched "chk"? You may also want to try clearing cache by starting you command with a "!". Like: "bc !chk"
I just looked in to adding Basecamp 3 support, and it looks like Basecamp hasn't released their API for v3 yet. They mention here that they plan on offering an API, but there is currently no timeline for it. I'm tracking the issue, so as soon as they announce it I will update the workflow.
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Edit: 4/13/2016
Basecamp 3 Support! Info here
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Provides easy access to Basecamp Projects inside Alfred 2. Allows you to quickly open a project in your default browser, or copy the url to the clipboard using "Cmd". This also supports multiple Basecamp organizations. This does not support Basecamp Classic.
Find it on
Packal: http://www.packal.org/workflow/basecamp
Github: https://github.com/johnthepink/alfred2-basecamp
Setup
Right click on the “bc” Script Filter and click “Configure”. Fill out your Basecamp information. Note that if you belong to more than one organization, you can enter them separated by commas. Have fun.
Please let me know if you have feedback, or send a pull request on Github. Thanks!