Aash, you don't need to create postgres2. When you did su - postgres from root, you were actually logging in as the postgres user. You can confirm this by executing the command "whoami" from the command line.
Emacs is a text editor. The error you are getting means that emacs is not installed, or it is not added to your PATH environment variable. You can add directories to your PATH with:
-bash-2.05b$ export PATH=$PATH:/bin:/usr/bin:/usr/local/bin
It is most likely that Emacs isn't installed though. You could try another text editor such as vi or kate.
