Windows Movie Maker Problem

I've made a video, published it to Vimeo with no problem. However, I need to publish it to You Tube but when I try, I get an error message (0x800488E7).

Any ideas what error this is? More importantly, any ideas how to fix it?

This is exactly the same video of about 40 still photos set to a music track of 4:30mins length, that I successfully published to Vimeo.

Thanks.