jps gives main class information unavailable

[Piyush Pawar]

Hello,
      I  suffered from this problem thst when i hit jps command it gives
I am using hadoop-1.2.1 on ubuntu in Multi-Node Cluster environment

3856 --main class information unavailable--
4533 --main class information unavailable--

When I reenter jps
the it will gives
jps
SecondaryNameNode
NameNode
JobTracker
After that NameNode goes in Safemode

Please Suggest some solutions I have tried  hadoop dfsadmin  -safemode leave
but its solves it temporarily.

Thank You!!!!!!!