Adding WAN GW crashes PFsense 2.0 Beta 4 build 0920
Just installed Beta4 and was on the WAN interfaces tab, attempted to add a WAN gateway to the interface, it went into a please wait, and eventually came back with 3 error boxes stating it was unable to add the gateway at this time.
This error occured, I would suspect, becuase I hadn't installed pfsense to the physical hard disk yet. After commiting to the HD I was able to add the GW
It works for me on a snapshot from today. Perhaps it was a part of what you were entering as the gateway name or description?