Astropy import error from a web application.

error.log

/usr/local/lib/python2.7/dist-packages/astropy/config/configuration.py:432: ConfigurationMissingWarning: Configuration defaults will be used, and configuration cannot be saved due to OSError:Could not find unix home directory to search for astropy config dir
  warn(ConfigurationMissingWarning(msg))
/usr/local/lib/python2.7/dist-packages/astropy/logger.py:490: RuntimeWarning: log file '' could not be opened for writing: Could not find unix home directory to search for astropy config dir
  '{1}'.format(log_file_path, unicode(e)), RuntimeWarning)
Traceback (most recent call last):
  File "testastropy.py", line 2, in <module>
    import astropy
  File "/usr/local/lib/python2.7/dist-packages/astropy/__init__.py", line 153, in <module>
    config.configuration.update_default_config(__package__, config_dir)
  File "/usr/local/lib/python2.7/dist-packages/astropy/config/configuration.py", line 688, in update_default_config
    if os.path.exists(cfgfn):
  File "/usr/lib/python2.7/genericpath.py", line 18, in exists
    os.stat(path)
TypeError: coercing to Unicode: need string or buffer, NoneType found

testastropy.py

import json
import astropy

result = {'version': astropy.__version__}
print json.dumps(result)

testpy.php

<?php

$result = shell_exec('python testastropy.py');

$resultData = json_decode($result, true);
var_dump($resultData);
?>