MS Outlook Not Responding: offlb.exe Issue

I have Exchange Server which I usually use my Outlook 2007 in it. My MS Outlook is not responding. It hangs for like 2 minutes and then it responds again and it hangs again after 5 to 6 minutes. It is irritating me.
It also hangs even though it is minimized. If I wanted to restore it from being minimized, it cannot be restored within a minute. If I write a message, it hangs again. The cursor is gone preventing me from typing further and comes back once again.
A text saying offlb.exe appears when Outlook hangs. Is it an error message or what? When Outlook responded, that text disappears and comes back as a cycle.
I don’t understand what this error is all about. It doesn’t seem connected to Microsoft Outlook or is it really the cause for this error? What is offlb.exe and what does it mean? Please help me.
