request cdd with cdd_serial 0 (or without cdd_serial) fails with TypeError: Cannot call method 'toData' of undefined

[gittiver]

POST / HTTP/1.1
Host: 127.0.0.1:6789
Content-Type: application/json; charset=utf-8
Accept-Encoding: gzip, deflate
Content-Length: 63
Accept-Language: en;q=1, de;q=0.9, fr;q=0.8, ja;q=0.7, nl;q=0.6, it;q=0.5
Accept: application/json
Connection: keep-alive
User-Agent: UnitTests/1.0 (iPhone Simulator; iOS 6.1; Scale/2.00)

{"message_reference":"0","type":"request cdd","cdd_serial":"0"}

fails with:
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Type: application/json
Date: Mon, 18 Mar 2013 10:24:34 GMT
Connection: keep-alive
Transfer-Encoding: chunked

3a
error

TypeError: Cannot call method 'toData' of undefined