Divide by Zero on Average Time Excel

I'm getting a #DIV/0 when calculating the average time from a range of cells.

A copy of the file can be found here;

http://ift.tt/19zdqM3

I have literally no idea why this is happening, nor can I seem to find a way around this.

I have checked the formatting of the cells, tried to re save the file, pull the data on to a new page. Nothing seems to work.

Any help is much appreciated.