This is the post I put on the Nokia support site. I have seen a number of people complaining that...as a for instance.... "Themes: feature not supported" error message appears. Post as follows......
"I love my 5800...for me personally it does everything I need from a phone.
However...last night I decided to back my phone up for the first time. Turned phone off and then this morning when I turned it on it had gone to a different theme then the one I had been using. Selecting "themes" gave me this message. "Themes: feature not supported" and I got kicked out of the menu. Reloaded backup and no change. Reset phone *#7370# and everything was OK. Restored just bookmarks and contacts and it screwed up again. Manually reinputted my contacts, re installed the theme I like and everything was OK again. Until I backed up the contacts ONLY...repeat...ONLY CONTACTS...no restore just a backup....turned phone off then on and again went to the faulty state of wrong theme and unable to change. This was after Nokia support advised not to backup settings when doing a backup.
This is not correct and I got the feeling from what he said that PC Suite isn't specifically programmed for the 5800. He mentioned an N95 in the conversation but I can't remember in what context. But it seems to me that something is seriously wrong in what should be a key part of the program.
I note that there are lots of people on the various web sites, MySymbian etc complaining of this problem and I bet its after using PC Suite to do any sort of backup/restore...even a partial one. Everything else works OK in PC Suite except this.....and its a bad thing to go wrong. My tip...don't use PC Suite for backups and restores. Interesting if anyone hasn't had this problem...
My PC Suite version 7.1.18.0 (latest)
5800 Firmware : 11.0.009
The problem has to be with PC Suite....... "