crash while trying to register anything

debug output:

````
debug: ffweimar: REG: Update Knoten: number=15, network_id=ffweimar, pass=2c:43:b6:1e:80:ca:6e:55:65:ae:53:4f:84:6b:f6:94, mac=f4ec38e96df0
debug: client error status=303, msg=MAC already registered!, number=40, mac=a0f3c1059236, last_seen=1372186731590, network=ffweimar, location=/ffweimar/knoten/40
debug: ffweimar: HEARTBEAT:  number=15, mac=f4ec38e96df0, last_seen=1378285566176, network=ffweimar, location=/ffweimar/knoten/15
debug: getfirstFreeNumber()
debug: register: id=network/ffweimar/1, mac=undefined, pass=undefined, ctime=1370978866109, mtime=1370978866109, number=1, location=/ffweimar/knoten/1, created_at=1370978866109, last_seen=1370978866109, network_id=ffweimar, resource=Knoten, 


...all knotens are displayed here....


ReferenceError: trynumber is not defined
    at /usr/local/share/registrator/lib/register.js:89:67
    at /usr/local/share/registrator/node_modules/resourceful/lib/resourceful/resource.js:167:13
    at Function.Resource.runAfterHooks (/usr/local/share/registrator/node_modules/resourceful/lib/resourceful/resource.js:94:12)
    at /usr/local/share/registrator/node_modules/resourceful/lib/resourceful/resource.js:163:14
    at /usr/local/share/registrator/node_modules/resourceful/lib/resourceful/engines/couchdb/index.js:209:5
    at Request._onResponse [as _callback] (/usr/local/share/registrator/node_modules/resourceful/node_modules/cradle/lib/cradle.js:233:9)
    at Request.self.callback (/usr/local/share/registrator/node_modules/resourceful/node_modules/cradle/node_modules/request/index.js:148:22)
    at Request.EventEmitter.emit (events.js:98:17)
    at Request.<anonymous> (/usr/local/share/registrator/node_modules/resourceful/node_modules/cradle/node_modules/request/index.js:876:14)
    at Request.EventEmitter.emit (events.js:117:20)
````