ok permissions look fine. Not sure why you give modifyworld.chat if you are also giving modifyworld.* but okay...
I'm really lost on this... Is it possible that you dont have the correct dimensions of the portal? Also, if there is an excess of obsidian blocks attached to the portal it wont work.
Do you have a screenshot of the portal you are trying to make?
Portals for me work fine. Members can't light the portals. I have to light it for them. When they try, they get the "You cannot do that here" The portals themselves are fine, they just aren't allowed to light them.