Question : Problem: "0 software updates found" for April 2009 even though Microsoft released the updates two days ago

Issue: "Zero software updates found" in the Configuration Manger Console for April 2009 even though Microsoft released the updates two days ago.
OS: Windows 2003 R2 Standard Service Pack2
System Center Configuration Manager Version: 4.00.6221.1000
Details: In the software updates section of the Configuration Manager Console, I have the vendor set to "Microsoft" the month and year set to "April 2009" and when I click "Go" to search for security updates, I get the message "0 software updates found."  I can't find critical updates or any other updates either.  I have a working internet connection (I can browse the web).  Last month and previous months I was able to see updates available in System Center without any issues.  I can't think of any changes that have been made to System Center or to the server.

I also see under System Status -> Site Status (in the left column):
Status: Critical
Errors: 0
Warnings: 78
ConfigMgr DB % Free: Automatically Grow
Trans Log % Free: Automatically Grow
Availability: Offline

Answer : Problem: "0 software updates found" for April 2009 even though Microsoft released the updates two days ago

It turns out I had  a group policy object for Windows Server Update Services that was corrupted.  I disabled this group policy and made a new group policy object with the same settings to resolve the problem.