Having problems running App Inventor in local

I am reading the documentation to run App Inventor in local, in the section How to build App Inventor from MITSource, the point 3.2 says (MAC version): "nohup <your-appengine-SDK-folder>/appengine-java-sdk-1.9.11/bin/dev_appserver.sh --port=8888 --address=0.0.0.0 <your-appinventor-folder>/appengine/build/war/ > serverlog.out &

"

I execute that command but it always says this in the log file:

Could not open the requested socket: Address already in use
Try overriding --address and/or --port.

I have changed the port but nothing and I do not know how to solve that problem. 

Does anyone what it could be?

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Are you changing the paths to wherever your app engine sdk is, and also to wherever your app inventor sources are?

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Yes, I have changed that.

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It sounds like you already have something running in that port. It can
be another copy of App Inventor, or some other software. You can try
the command 'jps' to see what java processes are running, and stop
them by their id.

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