http://support.veritas.com/docs/286545 (posted 4/25)

Within NetBackup, this repair will automatically occur when accessing the 
calendar dates of any schedule (Figure 1).  This could include the Calendar 
Schedule tab or the Exclude dates tab within a backup policy or the disk 
staging schedule of a disk storage unit.  When such a calendar component is 
accessed, it triggers Windows to verify the presence of all the files that are 
included in the NetBackup installation.  If any of these files are missing, 
Windows will automatically launch the installer to repair such missing files.  
As a part of the repair, the installer will automatically terminate any 
NetBackup services.  This will result in the immediate termination of any 
active backup or restore jobs. (emphasis is mine)

Hope none of the Windows users out there want to use the Calendar scheduler. =) 
And if that technote doesn't generate nightmares by itself, picture what 
happens when your NOC or Operations people stumble upon this issue at 2am in 
the middle of your largest backup window. Fun fun fun. 

Yet another reason to use UNIX Masters.....
- John Nardello