getting frustrated with imovies

hi all,

i am getting so frustrated with imovie, i have manged to create one progect very easily but now i have come across a problem when trying to upload videos

this is what i have done.

converted files from my camcorder to mp4's via handrake,

uploaded them to my ipad were i can view and play them

but cant view them when trying to add them in imovie,

i have also tried to add them view itunes were u use the file share section

pls pls help

alistair