Can you please post the output of following command here:
cat /home/hadoop/lab/install/hadoop-1.0.3/conf/mapred-site.xml

For quick help, you can use mapred-site.xml specified at following link:

https://www.inkling.com/read/hadoop-definitive-guide-tom-white-3rd/appendix-a/configuration

At this link, look for mapred-site.xml and use it for your setup.

Hope it resolves the issue.
Please post, if need further help.