WebSphere Version 5.1.0 display 5.0 at time Monitoring

hi i am new for WebSphere and rightnow i am working on WebSphere Monitoring.

see i am facing one problem as below.

i installed websphere version 5.1.0 and then i am taking the Version and other information through AdminClient and PmiClient.

but though i installed version 5.1.0 but at time when i fetched version info from WebSphere Jmx agent(Or MBean) it is showing me Version as 5.0.

this is what the actual problem, i am not able to understand this,because i am insalling 5.1.0 then why it is showing me 5.1 instead of it should show me 5.0.

can any one help me out?

i include all the legal jar files from WebSphere\lib and WebSphere\java\jre as well as i am not using any thirdparty tool for this.

pls help me i am confuse and i need urgent help.

thanks in advance
Lirin