I am new to MongoDB. I am trying to install MongoDb 3.0 on Ubuntu 13.0 LTS, which is a VM on Windows 7 Host. I have installed MongoDB successfully (packages etc.), but when
Alternative to the answer provided by KurioZ7, you can simply set the permissions of the .sock file to the current user:
sudo chown `whoami` /tmp/mongodb-27017.sock
This does the trick for me if I want to run mongod without sudo. If I delete the file like in KurioZ7s answer, I will simply get the same error the next time I restart my machine.