gettext errors with wxPython in linux

[ianaré]

given the foolowing code:

import gettext
gettext.install('messages', './locale', unicode=0)

<snip>

    def __init__(self, parent):
        # initialise preferences
        self.prefs = self.getPrefs()

        # initialise language:
        language = self.prefs['language=']
        langdir = self.realPath('./locale')
        Lang = gettext.translation(domain='messages',
localedir=langdir, languages=[language])
        Lang.install()

<snip>

    # return full path:
    def realPath(self, file):
        return os.path.join(sys.path[0],file)
....

and using following structure:
application_folder/locale/fr/LC_MESSAGES/messages.mo

works fine in windows2k, XP, however under linux:
IOError: [Errno 2] No translation file found for domain: 'messages'

what gives? thanks.