This is not a duplicate topic. I created a post here:
http://forums.retrospect.com/index.php?/topic/150552-retrospect-configuration-gets-corrupted-too-easily/
with a solution for other users. This post is just for the bug report.
The Config80.dat file is too fragile and does not survive forced power downs on the backup server. The current method of saving the configuration should be replaced with something that is more robust. The configuration file is also large - it's 80MB in my case - which suggests that maybe its design should be refactored or else the content split up into separate files so that the basic server configuration is less likely to get corrupted.