To correct this, re-name your file to have no spaces or special characters (!@$&%*-.~ etc) - then re-add the download to your Pushpage Issue. If the issue has already been sent, you will need to re-send this with the new attachment.

The text that you use as a hyperlink can also cause an error, such as '~*Download This*~', as this becomes a part of the link when the pushpage is sent, appended to the link as '&lbl=~+*+Download+THIS+*+~'