It seems that the recent SkyDrive upgrade is now causing some issues with SkyDrive and OneNote users on their Windows Phone when synchronizing documents and notes between the cloud and a handset (check out our howto for more information). Users are reportedly met by errors stating that the document and/or note is not available on the server.
Rest assured that your content has not been lost. All that's required is to reset Office on Windows Phone, which will wipe locally stored files and clear pinned items. Check out the following steps:
Go to Settings
Go to the Applications pivot
Press the Reset Office button (if you get a message that Office could not be reset, reboot your phone and try again)
Source: Windows Live Blog, Live Help