It seems like you are using Nutch 2.x.
And the args you passed looks like the one from the documentation of the Nutch 1.x REST service. 
Could you please tell which documentation did you refer to ?

Sujen Shah
M.S - Computer Science (Class of 2016)
University of Southern California

On Tue, Apr 7, 2015 at 3:58 PM, Mahmoud Gzawi <gzawi.mhmd@gmail.com> wrote:
Hi everyone.

I'm having a trouble creating a job in nutch server. if any one could help!

I'm trying to create a job in nutch server and i'm stuck at the begining:

    "args": {"crawldb":"crawl", "url_dir":"/.../apache-nutch-2.3/runtime/local/url/"}

and here's hadoop log

2015-04-08 00:37:52,102 INFO  api.NutchServer - Starting NutchServer on port: 8081 with logging level: INFO ...
2015-04-08 00:37:52,137 INFO  api.NutchServer - Started NutchServer on port 8081
2015-04-08 00:38:31,384 ERROR impl.JobWorker - Cannot run job worker!
    at org.apache.nutch.crawl.InjectorJob.run(InjectorJob.java:207)
    at org.apache.nutch.api.impl.JobWorker.run(JobWorker.java:64)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)

Can anyone tell me what i'm doing wrong!
Thanks in advance.