iMovie show nothing but black

Dear Sir/Madam,

I recently doing iMovie video editing in my iPad (3rd generation with ios 5.0.1). The problem I had as I played it in a preview, it show only the first picture and the last picture while the other pictures that in the middle show nothing black but the music still playing like usua l. I try to export it to camera roll but I still face the same problem just like in iMovie. What can I do to solve the problem ? Please help me out !!!!

Sincerely,

Justin P.