The security validation for this page is invalid

Error:

I received the following error while uploading files to a sharepoint document library from an asp.net application.

The security validation for this page is invalid. Click Back in your Web
browser, refresh the page, and try your operation again

Resolution:

Add following lines of code before the Update() method on SPFolder is called.

site.AllowUnsafeUpdates = true;
web.AllowUnsafeUpdates = true;