Rootkit?

Hi guys i just came to know something about rootkits. i guess its something which hooks up with API's and hands over the controls to a attacker. I used AntiHookExec tool and it gave a html file . its showed something with "Checking exports of KERNEL32.DLL for discrepancies" thing which i didnt understand.

*img405.imageshack.us/img405/6849/rootkit9ok.th.gif

what is this ? is there a problem with my pc?

any comments??