You get error code 0x80090016 whenever you attempt to create a new Scheduled Task on a Windows 2003 machine

4. Start your computer in Safe mode, and then log on as administrator.
5. Double-click My Computer, and then click Folder Options on the Tools menu.
6. On the View tab, click to select Show hidden files and folders, and then click OK.
7. Backup and then delete all of the files in the "C:\Documents and Settings\All Users\Application Data\Microsoft\Crypto\RSA\S-1-5-18" folder.
8. Restart your computer, and then see if the issue is resolved.


http://blogs.msdn.com/b/john_daskalakis/archive/2009/04/07/9535705.aspx