FireStarter not installing

On selecting the USE THIS SOURCE for Firestarter in Ubuntu Software Center
I get the following error

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/aptdaemon/worker.py", line 116, in _process_transaction
    self.update_cache()
  File "/usr/lib/python2.6/dist-packages/aptdaemon/worker.py", line 426, in update_cache
    self._cache.update(progress, raiseOnError=True)
  File "/usr/lib/python2.6/dist-packages/apt/deprecation.py", line 103, in deprecated_function
    return func(*args, **kwds)
  File "/usr/lib/python2.6/dist-packages/apt/cache.py", line 309, in update
    raise LockFailedException("Failed to lock %s" % lockfile)
LockFailedException: Failed to lock /var/lib/apt/lists/lock