I'm not sure why that's happening, actually. JFBConnect should be loading the language file for JomSocial and reading those fields, but it's possible we mixed something up.
Can you try enabling Language Debug in the global configuration area? When you do, there should be dots or question marks around anything that Joomla thinks is translatable.
If there aren't those characters around those text fields, can you try the following code change? In the /plugins/jfbcprofiles/jomsocial.php file, around line 83, you'll see:
$groupHtml .= $field->name . "" . CProfileLibrary::getFieldHTML($field) . "";
Change that to the below (adding the JText::_( ) around the $field->name stuff:
$groupHtml .= JText::_($field->name) . "" . CProfileLibrary::getFieldHTML($field) . "";
Hope that fixes things, but let us know either way how it goes!
Thanks,
Alex
Missing Profile fields names - Translation on register jfbc
