There was a post way back from you though that in some circumstances marriage outside of your church was accepted. Why is this case different?
The basic gist is that Catholics need to have Catholic Church-approved marriages. Usually this is in the Church, but permission can be obtained to have the wedding at a Protestant Church.
A Catholic who marries either at a J-P or in another Church without permission is not considered to be in a valid marriage.
Non-Catholics can marry however they please and the Church generally accepts these as valid.
SD