unable to auto-detect email address

Well, the message is pretty much self-explanatory. You did not tell git what your name and email address is.

Open a command line and type:

git config --global user.email "you@example.com"
git config --global user.name "Your Name"

Of course you should enter your real name and email. Afterwards git knows who you are and is able to insert this information in your commits.

Seems like smartgit does not add the git binary to your path. You have to add its path to the PATH environment variable or first change to the corresponding directory. You can find a screencast here: http://blog.dragndream.com/?p=97