Pc to ipad photo stream

Hi I am trying to stream photos from a pc to my iPad, which has worked in the past. But now it won't work?
When moving photos into photo stream/ uploads on the pc I accidentally added some video file, I have a feeling they are stopping the transfer of photos,
But when I try and move or delete the videos I have the message 'the action can not be completed because the file is open in applephotostreams.exe'
I have tried everything to get rid of the but can't do it, any ideas?

Moving this to the Help Section...