How do I recover from a broken gem?

I've recently started working on my first Sinatra/CouchDB app and kept running into a SystemStackError: stack level too deep error. After a ton of googling, I've discovered that one of the gems I've been using, json-1.4.开发者_如何学编程3, is apparently broken :/

I uninstalled the gem, and installed json-1.4.2 instead, but I'm still getting the error. I'm wondering if I need to do something to make sure that 1.4.2 is being used now instead of the broken 1.4.3?

Any help would be greatly appreciated!

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you can list the gems to see if you have two gems.