I have the same problem but I installed Mcafee spam killer, which I than removed.  I ran the troubleshoot program and it said I needed a Microsoft Update.  Microsoft's web site said I already had the update installed.  Dell wants me to pay them $100.00 to trouble shoot it.  Microsoft and Mcafee say it is Dell's problem because Outllook and Spam Killer came with the machine.  I purchased my Dell because I was told the technical support was great.  I have yet to be impressed.

I found the answer after a few hours on the web...
Close Outlook>right click Start Button>Explore>Documents and Settings>User Name>Application Data>Microsoft>Outlook> then reneme the .srs file (I just put a $ in front of mine).> Restart Outlook. Outlook won't be able to find the renamed file and generates a new .srs file. I beleive it's a send/receive file.

Hope it works for you too.

Well that problem is cleared up but now Outlook does not send the right password and ID to my ISP.  It tells me my ISP rejected my login.  I contacted my ISP they have no problem logging in with my account name and password.  When I login to the web based email it works fine.  I was told my outlook was corruppted so I reinstalled.  It did not seem to reinstall Outlook, I mean adress book etc remained.  After like the fourth try now it says it can't find the installation patch package and will not let me try to reinstall or uninstall Outlook.