After effects fail

I have tried so many times to work after effects and i swear i cant get my head round it. I'm sure i've been doing exactly what i've been shown in the after effects sessions but it just isn't working for me! Below are some screen shots of the processes i've been through with it.

Began by changing the settings of a new composition and the frame rate to 12fps

Added my images as an image sequence

CANT FIND SOME OF MY IMAGES?!

I decided to carry on and just see what happened, and if they were important images.

Here i had to resize some of my images, obviously too high (probably 300dpi) 

at the beginning it looked like it was working (albeit going wayyy too fast on the preview)

..And then the lost images. I really don't understand this and i've spoken to course mates which this has happened to them, they said they moved files around and somehow it sorted itself out. 

I have tried this so many times, uploaded the files again, made new folders, copied the images, agh i just cant get them to upload!

This is way too stressful for me with only a few days to go before the deadline so i am going to have to resort to imovie. It doesn't have all the features of after effects, but what good are features if i cant use them anyway. From my tester animations that i created on imovie i think that it will work just as well, i just may have to jig around some of my images and music because i have created the animation with 12fps and imovie only allows me to use 10.