the problem's inside Sprite 262: in the actionscript on
sprite 261(instance name pics). phew! you're using the variable x
inside your onClipEvent (enterFrame) without initialising it first.
in your onClipEvent (load) add the line x=0;
lots of other comments i could make on your code - eg avoid x
as a variable name as i believe it's a reserved word, try to avoid
placing script on symbols or inside symbols as it makes it hard to
debug/find, but anyway it should be working now.