It seems to be working for me using the latest version of mojoPortal. Nothing has changed about our Like button. Occasionally there are bugs at Facebook and sometime bugs that only affect some users and not others or some urls and not others. For several weeks I was unable to post links to our Facebook fan page but eventually they fixed the bug and it started working again.
I think it will sort itself out eventually and is not caused by mojoPortal.
Best,
Joe