Impossible to read on a Mac an After Effect video made on windows

Dear all,

We cannot find the answer to this problem anywhere, so we hope you can help us.

We have to modify with a McBook pro an After Effect template initialy made on Windows. The video starts well, but after 10 seconds, the sound and the image are slowing down to 6 to 10 image per second instead of the initial 30, so we can not see or listen to anything correctly. We have tried to change the number but it does not solve anything. The Mac we use seem not to be the problem as this is a brand new powerfull machine:

FYI, when we open the template, we get messages about the impossibility to open some files:

or that the compression of the source file is not taken over:

Can you please tell us what we can do to solve the problem and modify the template smoothly ?

Thanks in advance for your anwers and best regards.