add_node fails with no specifc error on recent builds

add_node rest api calls are failing in more recent builds.

the error happened 14:15:52

[2011-04-16 14:15:52,705] - [rest_client] [MainThread] - INFO - add_node response :

{'status': '500', 'content-length': '44', 'server': 'Membase Server 1.7.0r_85_g635f746', 'pragma': 'no-cache', 'cache-control': 'no-cache', 'date': 'Sat, 16 Apr 2011 21:15:52 GMT', 'content-type': 'application/json'}

content : ["Unexpected server error, request logged."]

i see this error in the diags which could be related to the add_node call failling:

moxi<0.289.0>: 2011-04-16 14:15:04: (agent_config.c.650) ERROR: bad JSON configuration: Empty serverList ({
moxi<0.289.0>: "name": "default",
moxi<0.289.0>: "nodeLocator": "vbucket",
moxi<0.289.0>: "saslPassword": "",
moxi<0.289.0>: "nodes": [],
moxi<0.289.0>: "vBucketServerMap": {
moxi<0.289.0>: "hashAlgorithm": "CRC",
moxi<0.289.0>: "numReplicas": 1,
moxi<0.289.0>: "serverList": [],
moxi<0.289.0>: "vBucketMap": []