Issue solved.
Basically, JFBConnect has a text field parameter called "Social Tag Admin Key" which if set, requires tags to be {JFBCTagName key=xxxx} to prevent random users from adding tags.
EasyBlog should have an additional field under the Settings > Integrations > JFBConnect field for this to be entered and if a value is detected, then the tag should be {JFBCLogin key=xxxx} and just {JFBCLogin} if empty to work properly with JFBConnect.
Might also would be worthwhile having some text above the buttons to tell people to login or register with the buttons although considering that Stackideas seems to have lost track of what language constants you have in play (several undefined ones in the various modules), not so sure it is a good idea for you to create new ones