The output you see there is no error at all its simply the actual contents of your command prompt.
Coming to the point you pointed out in comments. You nearly had it right. You should use
PS1= to set the input prompt and not
$PS1. To get it to show the user name and the hosts name your approach was as well slightly wrong the full line for that would be:
Or if you want the simple Ubuntu style prompt:
# For use with force_color_prompt=true
# The normal one
On top of this saying, as long you not changed the lines in your
.bashrc file or in
/etc/bash.bashrc you can simply close your terminal and reopen it again, if you're on a GUI that is. This as well will reload the
.bashrc file and restore your command prompt.