title: No such file or directory with subprocess.Popen, not caused by string command
body: <p>I'm running a webservice which operates on wav-files, but I don't want to allow just any upload, so I check the duration of the uploaded file first with the following code:</p>
  
  <pre><code>os.chdir("/home/me/bin")
  proc = subprocess.Popen(['duration',wav],stdout=subprocess.PIPE,stderr=subprocess.PIPE,shell=False)
  out, errors = proc.communicate()
  time = int(float(out.strip()))
  if time &gt; MAX_TIME:
      sys.exit(1)
  </code></pre>
  
  <p>This has been working fine for several months, but recently (after a migration, I should add) I get the following error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/home/me/webservice.py", line 100, in &lt;module&gt;
      proc = subprocess.Popen(['duration',wav],stdout=subprocess.PIPE,stderr=subprocess.PIPE,shell=False)
    File "/usr/lib64/python2.6/subprocess.py", line 639, in __init__
      errread, errwrite)
    File "/usr/lib64/python2.6/subprocess.py", line 1228, in _execute_child
      raise child_exception
  OSError: [Errno 2] No such file or directory
  </code></pre>
  
  <p>This error seems to be mostly caused by the use of a string for the command instead of a list, but that's not the case here. When I try to reproduce this error in a separate script, I can't.</p>
  
  <p>Anyone have any idea what might be the cause here?</p>