VU solo loosing stored channels

hi i have a vu solo bought plug and play put channels into the favourites list into a better order but had to unplug the box and when plugged back in they had gone but the channels already in the box when purchased remained,only the few i had downloaded and put into the favourite list had gone,done this manually with the remote.it is the same proceedure with my dm800hd but the channels never dissapeared from that box...hope that made sense..any help appreciated...cheers