injector failing

hi

earlier my crawl was working properly but i dunno some error
has crept in
the crawl is not working properly.
the output is something as follows
[rootlocalhost nutch-0.9]# bin/nutch crawl urls  -dir
karan
crawl started in: karan
rootUrlDir = urls
threads = 10
depth = 5
Injector: starting
Injector: crawlDb: karan/crawldb
Injector: urlDir: urls
Injector: Converting injected urls to crawl db entries.
Exception in thread "main" java.io.IOException:
Job failed!
        at
org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:604
)
        at
org.apache.nutch.crawl.Injector.inject(Injector.java:162)
        at
org.apache.nutch.crawl.Crawl.main(Crawl.java:115)

please need assistence