Gnome Terminal not opening

As Ipor Sircer suggests, if you can open another terminal, you can run gnome-terminal from there.

Alternatively, you can dump gnome-terminal's output to a file: assuming you're running GNOME, press AltF2 and enter

sh -c "gnome-terminal > ~/gnome-terminal.log 2>&1"

Then you'll find all the output in ~/gnome-terminal.log.