If you are using avast! Free then this may help you . . .
From the avast! GUI go to “Settings” → “Troubleshooting” → “Redirect Settings” → “Web”. In the list of “HTTP port(s)” remove the entry for “8888”. Close all avast! windows and try connecting again with Filezilla.
BTW, you should probably update to the latest version of avast! (2014.9.0.2008).