Hi Ashish,
6.0.0.1?!?!?!?! you are a lot of years out off support
Anyway for apply the last FP 6.0.2.43 you need....patience because is a tedious task
If you have a Deployment Manager, then is mandatory to upgrade first Deployment Manager server (node)
0.- Backup your server(s) (or at least WEBSPHERE_HOME directory)
1.- Stop all your server(s) DMGR, APPSERVERs
2.- Apply Refresh Pack 6.0.2 and FP 6.0.2.21
Download and install Update Installer for 6.0.2 (in all your servers)
Update Installer for WebSphere Application Server V6.0 releases www-01.ibm.com/support/docview.wss?rs=18... Download and install (First DMGR then APPSERVERs)
6.0.2: WebSphere Application Server V6.0 Refresh Pack 2 www-01.ibm.com/support/docview.wss?rs=18... Download and install (First DMGR then APPSERVERs)
6.0.2.21: WebSphere Application Server V6.0.2 Fix Pack 21 www-01.ibm.com/support/docview.wss?uid=s... 3.- Apply FP 6.0.2.43
Download and install Update Installer (in all your servers)
IBM Update Installer V7.0.0.37 for WebSphere Software www-01.ibm.com/support/docview.wss?rs=18... Download and install (First DMGR then APPSERVERs)
6.0.2.43: WebSphere Application Server V6.0.2 Fix Pack 43 www-01.ibm.com/support/docview.wss?uid=s... 4.- Start all your server(s)
Hope this helps. Tell us if you need more support
Regards