Had this happen, was trying to figure out why MAME wasn't working. I got this error and RetroFE just would not respond, I ended up leaving it as I wanted to see the bug I was getting. I've had a few unresponsive moments since I reinstalled Linux ( I made a mistake trying to change the bootup images and couldn't get Linux back) and this error kind of confuses me. It ends the string with a Segmentation fault (core dumped).