pdf uploading

I have attempted many, many times to upload a pdf file to the wordpress website. Once I go to add media and select the file, all I get is Add media files from your computer
The uploaded file could not be moved to E:\www-data\snoopy\Inetpub\wwwroot\subsite/wp-content/uploads. Any help would be greatly appreciated. We are a youth club who uses the website for basic information and results. Charlie