Following on from the FXCM hacking OANDA have reported a "platform issue"
Oanda's twitter reporting problems and so are the Forexlive readers on the FXCM hacking post
Nothing to suggest the two are related as of yet. Oanda are saying via Twitter to contact frontdesk@oanda.com to open and close positions
Update: Our trusted readership report that they are now able to log back into accounts