The first error you might face while using Mercurial might be this:
$ hg commit abort: no username supplied (see "hg help config")
Mercurial needs a username and email for almost all its operations. It looks for this in a Mercurial configuration file.
For Windows: The Mercurial configuration file is named
Mercurial.ini. You will find a copy of this file in the Mercurial installation directory. Copy it to your
%HOMEDRIVE%%HOMEPATH% directory (
C:\Users\AverageJoe\ on Windows 7).
For Linux: The Mercurial configuration file is named
.hgrc. Create a file with this name in the home directory of the user if not already there.
Add these two lines to the Mercurial configuration file:
[ui] username = Average Joe <email@example.com>
Mercurial commands should work fine after this.
Tried with: Windows 7 Enterprise, Ubuntu 12.04 and Mercurial 2.0.2