Have the alert response times been set or are the default settings still in place? To set the alert response times go to the BackupExec directory and locate BEutility.exe (located under the NT folder). The basic steps are double click BEutility.exe; add the server (File, New, enter server name); right click the server name, select Refresh (Status should change to running). In the task pane on the left side of the window click Edit configuration. Under Automated Alert ... select the appropriate times.
Open BackupExec, go to the Alerts tab, in the Task Pane select Configure Alert Categories. Some you change and some you can't.
Hope this helps.