dissapeared, like you saw them browsed games/settings and then they were gone?
or updated wiiflow, did something to your sd card/usb drive, and when you tried to load the new one no covers where there?
in either case, check the folder structure, apps folder seems to be fine otherwise you would be able to load it.
if that is gone you have to redownload the covers through the settingsmenu for example (or find a backup of it from your old install, guess you removed that as well to have the new wiiflow working..only boot.dol in \apps\wiiflow would really needed to be replaced, drive:\wiiflow holds themes, covers and some settings)
make sure you only have one installation present sd card or usb harddrive.
Why don't you say Hello in the introduction section too