I just purchased and Ubiquiti EdgeRouter PoE, model number ERPoe-5. The GUI loaded for me initially, but no longer does after I attempted to upgrade the v1.2 that it came with to the current 1.9 firmware. After I booted into the 1.9 firmware, I attempted to run the "basic setup wizard", after which I now receive this error in the GUI: "Fatal Error: Unable to load the router configuration". I attempted to reboot into the old system image, v1.2, but the problem is now also present there. I cannot get the GUI to load in either image, and deleting and installing new images on other versions, like v1.8.5, has not helped either. Nor has doing factory resets in any of the images helped me.
I have isolated the error that is received: in the /var/log/lighttpd, the following error is logged every time I attempt to visit the GUI in my browser, so it appears the problem is due to lighttpd crashing. Here is the reason it logs for the crash, and I have been unable to figure out why this is happening:
2015-01-01 00:01:58: (mod_fastcgi.c.2695) FastCGI-stderr: PHP Fatal error: Cannot declare class UBNT\Core\Api, because the name is already in use in /var/www/php/core/classes/api.php on line 14
Note that the timestamp of the log entry is way off, simply because I haven't set the date on the router or configured NTP yet.