Reopening saved text files doen't work

When reopening a text file saved with Save As nothing happens. The terminal is giving the following error:

Traceback (most recent call last):
  File "/usr/share/openteacher/openteacher.py", line 692, in openFunc
    dom = parse(open(openFilename))
  File "/usr/lib/python2.5/xml/dom/minidom.py", line 1915, in parse
    return expatbuilder.parse(file)
  File "/usr/lib/python2.5/xml/dom/expatbuilder.py", line 928, in parse
    result = builder.parseFile(file)
  File "/usr/lib/python2.5/xml/dom/expatbuilder.py", line 207, in parseFile
    parser.Parse(buffer, 0)
xml.parsers.expat.ExpatError: syntax error: line 1, column 0

I also get the same error if I open a wrong formated text file