SCO had a Backup Manager back in Openserver 5.0.0, so your problem probably isn't related to the difference in versions.
One thing to try is an audit of your installed SCO software. To do this, load the Software Manager (custom), tab to the listed software window, move down to where the SCO Openserver System is listed (mine says SCO Openserver Enterprise System (ver 5.0.6j)), and press enter to select it. You will see the list of items expand and branch out as you select different things. Under SCO Openserver System, select the item that revers to UNIX, then the item for System Administration, and finally Backup Subsystem (I am guessing your 5.0.4 system follows this same path). Backup Subsystem should now have an * showing on the left. Press Tab to go back to the menu at the top of the screen, open the Software menu and choose Verify Software. You will see a list of 5 different "check for's" which can be run at your discretion. This process will find any discrepancies between the software running and the installed software, alert you to them, and in some cases even correct them. You should be aware however that not all discrepancies indicate a problem. You can also run this process on lower branches of the software list, but the more items the branch contains the longer it takes, and the more difficult it is to sort through the reported information. This is just a tool which might help you isolate the cause of the problem.
To upgrade to 5.0.5 you will need to obtain the upgraded software and any applicable licenses, and install and configure it, but you probably don't need to upgrade to 5.0.5 to fix this problem.
