SharePoint Backup Error

If you get the following error message while trying to run the backup process from Central Admin or through stsadm.

"Object WSS_Content failed in event OnBackup. For more information, see the
error log located in the backup directory. SqlException: Cannot open backup
device 'C:\SharePoint\backup\spbr0002\00000012.bak'. Operating system error
3(The system cannot find the path specified.). BACKUP DATABASE is terminating
abnormally. "

To resove this problem, make sure you are UNC path for backup and the account running SQL service has write access to this path, for more detail -
http://support.microsoft.com/kb/207187


Backup plan may fail with the following error
************************** Errors ***********************
Path: http : / / web / sites / wwwwww, Status: Failed.
Error Message: Site Level Backup Backup() error:Write error on file
"sharepoint_bak.dat".
******************************************************

A likely reason that this is failing is that the location where the file is being written to does not have sufficient space.