why i can't i find my iMovie user preferences?

im having trouble exporting a movie i made in imovie, all my others export fine, its just this one for some reason. when i try to export i get the -50 error. a lot of people on the net say try deleting your imovie user preferences so i thought i'd give that a go, only, i cant find them! im going the usual route, ie,

click "go" menu, choose "home", open "library", clcik "preferences" then delete "com.apple.imovie.plist". when i do this, i have to type "library" into the search box and when i click on it, i have to do the same for the "preferences" folder. nothing is just there and easy to find as other people seem to suggest. and when i finally click on the preferences folder the only file thats in there is a help manual for the program "Audacity" and nothing else! where are my user preferences???? HELP! thanks!