Ooooh! First, let me say this for everyone to read: Be VERY careful mucking about in iFile. Changes in there to your iPad could lead to disastrous consequences (read: leads to having to restore your iPad - maybe lose jailbreak).
/Public service announcement.
Pollpixx - Is that wallpaper that's messed up the one for the theme? Cause if it is, TBH, the easiest thing to do is to go back to Cydia and remove/reinstall that theme. Actually, you may be able to get away with just a reinstall, AFAIK. That'll put it back the way it was...
Its in the theme indeed, will restore it, thanks for the warning, i screwed up some phones before with my tweaking skills and still i didnt learn from it :lol