i was going to say what rkrox79 said....
i use winkflash exclusively...i save all layouts at 300dpi and create them the exact same size i entend on printing them...
meaning, if i know im going to print 8x10 or 5x7....that is the size i make the layout....i never resize once its made....i dont know if thats why i never have problems....but that is just what i do
good luck!