Object reference not set to an instance of an object when trying to check out document from library WSS30

Object reference not set to an instance of an object when trying to check out document from library WSS30

Resolution:

–>Open you Central Administration site and go to “operations”
–>look for “Alternate Access Mappings”
–>In the page you will find “Alternate Access Mapping Collection” and it will say “Show All”
–>Click on the small arrow point downwards on this “Show All” location and you will get “Change Alternate Access Mapping Collection”
–>Go ahead and choose the Web Application which is responsible for the problem site
–>You will see that there is a URL already showing in “Default” zone
–>You need to specify the URL which is giving you problem in the “Intranet” zone. So it will see like this:
Default: http://matrix
Intranet: http://yagyashree.org
–>Performed IISRESET
–>Now everything should be working fine, you should be able to check-out and edit the office documents