Help please

please,
i need your help!
i have a big assignment to schedule in the end of the month/
i’ve made a game which made of pictures and videos (flv),
and when i’ve inserted the third flv movie i tried to test my project.
… and when i have exported it, it reaches the end and just doing nothing: no errors, no file, just nothing.
my project is on 1920X1080 resolution, i have 23 videos of 10 seconds each, that i need to insert, and the quality is 1500 bits.
the first two inserted movies succeeded, but from the third and above, nothing happend.

it’s really really important.

thank you very much for any kind of help