Of the places David McClister and I tried to locate in Syria in 2002, this was the most difficult.
See the Index of articles about Babylon, including a few references to Riblah, here.
Zedekiah, puppet king of Judah, tried to escape capture by the Babylonians. He fled Jerusalem but was captured on the plains of Jericho and brought to Riblah. There Nebuchadnezzar passed sentence on him. His sons were slaughtered in his sight and he was bound with brass fetters and taken to Babylon. The date was 586 B.C. (2 Kings 25:5-7; see also Jeremiah 39:5-6; 52:9-10).