I have a problem with deleting the old backups first. If a database becomes 'suspect' the backup will fail. In that case you need a backup for a restore. If you do not notice the problem in time, the old backups may be gone!

Also I noticed in 'BuildNotifyStep' a small error in the version check. You should use 'xp_smtp_sendmail' with version 7 or 8, not 9.

Perhaps you could give the application a return code to catch by the SQL agent, in case of an error..