Mod_python error: "PythonHandler invenio.webinterface_layout"

Traceback (most recent call last):

  File "/usr/lib64/python2.4/site-packages/mod_python/apache.py", line 299, in HandlerDispatch
    result = object(req)

  File "/usr/lib64/python2.4/site-packages/invenio/webinterface_handler.py", line 298, in _profiler
    return _handler(req)

  File "/usr/lib64/python2.4/site-packages/invenio/webinterface_handler.py", line 316, in _handler
    return root._traverse(req, path)

  File "/usr/lib64/python2.4/site-packages/invenio/webinterface_handler.py", line 210, in _traverse
    result = _check_result(req, obj(req, form))

  File "/usr/lib64/python2.4/site-packages/invenio/websubmit_webinterface.py", line 490, in index
    return _index(req, **args)

  File "/usr/lib64/python2.4/site-packages/invenio/websubmit_webinterface.py", line 478, in _index
    return home(req,c,ln)

  File "/usr/lib64/python2.4/site-packages/invenio/websubmit_engine.py", line 1014, in home
    catalogues = makeCataloguesTable(ln)

  File "/usr/lib64/python2.4/site-packages/invenio/websubmit_engine.py", line 1041, in makeCataloguesTable
    top_level_collctns = get_collection_children_of_submission_collection(0)

  File "/usr/lib64/python2.4/site-packages/invenio/websubmit_dblayer.py", line 429, in get_collection_children_of_submission_collection
    qres = run_sql(qstr, (collection_id,))

  File "/usr/lib64/python2.4/site-packages/invenio/dbquery.py", line 231, in run_sql
    db = _db_login(relogin = 1)

  File "/usr/lib64/python2.4/site-packages/invenio/dbquery.py", line 110, in _db_login
    use_unicode=False, charset='utf8')

  File "build/bdist.linux-x86_64/egg/MySQLdb/__init__.py", line 81, in Connect

  File "build/bdist.linux-x86_64/egg/MySQLdb/connections.py", line 188, in __init__

OperationalError: (2002, "Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (111)")