Projects corrupting when exported

Hi there, 

The last 2 projects that I've completed have corrupted when exporting in Rush. Can anyone help?

I got an error message when I tried to open the first one on my laptop after exporting. I've done loads of projects and this has never happened. I wondered whether it might be the raw files so I deleted that and began another project, this one has exported however I can only play 4 mins of the file and then it just stops. I've tried playing on 2 different media players on my laptop and the same happens with both.

Both play fine in Rush. Help please!!!

Thanks,

Claire