Traceback (most recent call last) error appears on terminal

Traceback (most recent call last) error appears on terminal

Recently i encountered a weird problem in Linux mint 14.When i enter any command (e.g $ ls) in terminal it throws error saying Traceback (most recent call last).
Detail Description of the error is
$ ls

Traceback (most recent call last):

 File "/usr/lib/command-not-found", line 21, in <module>
    os.execvp("python3", [sys.argv[0]] + sys.argv)

 File "/usr/lib/python2.7/os.py", line 344, in execvp
    _execvpe(file, args)

File "/usr/lib/python2.7/os.py", line 380, in _execvpe
    func(fullname, *argrest)

OSError: [Errno 2] No such file or directory**
Same problem appears for all of the command.
Can anyone help me fixing this error
Thanks in advance