Zip Archives

Just been setting my site and noticed when I download one of my test purchases I cannot open the zip archive. This only happens when I download from the website itself. If I download the same archive from my FTP it seems to open perfectly fine.

I have tried setting the temp zip creation folder to both the temp folder and the logs folder but still neither are allowing me to open the file once it has been downloaded.

Any help to get this sorted would be much appreciated.