I am also having this issue. Have two wordpress sites, one is 3.4.1, other is 3.5.1, both running BackupWordpress 2.2.1. Both running on IIS7 on Windows server 2008. I change the occurrence settings of every schedule, yet it doesn’t seem to do anything. Tried deleting the schedules and adding new ones, deleting the plugin and reinstalling it, nothing seems to work.
e.g. I have database set to backup hourly, the message says “Backup my 22 MB database hourly on the hour, store only the last 30 backups on this server.”, yet when I highlight the “hourly on the hour” it says “The next backup will be on 02/26/2013 at 11:00 PM”, but it just seems to backup at random times regardless. Here is a screenshot
https://www.dropbox.com/s/p6fagy2ikl8kf8t/Untitled.png