I was told by support to create a backup of my docks, which was impossible because OD needs to run in order to create a backup. That was the problem to begin with. Since I haven't seend the solution here, I'll post how I fixed it, it's very simple actually. By the way, in my case the problem was due to a corrupt settings file.
Close OD and make sure it's not running.
Go to: C:\Users\username\AppData\Local\Stardock\ObjectDockPlus
There are 4 files, one of them is CurrentTheme_Backup.ini. Delete CurrentTheme.ini (make a backup first). Copy/paste CurrentTheme_Backup.ini and rename it as CurrentTheme.ini.
Restart OD.
This might not solve every instance of that problem, but for corrupt settings, it's the easiest way. Same for backing up: the files in that folder (AppData\Local\Stardock\ObjectDockPlus), along with Program Files\Stardock\ObjectDockPlus are what needs to be backed up to re-create your docks. I never got any SD application to do the job.