2 problems i can see.
1) the download code:
<?php
WA_DFP_SetupDownloadStatusStruct("WA_DownloadResult1");
if(isset($_POST["Download"])){
WA_DFP_DownloadFile("WA_DownloadResult1", "digital/", "Capital H Health.pdf", "[FileName]", false, false, false, "", "", "", "");
}
?>
is set to use a form element named "Download" for the trigger. This would be fine if your submit button where a standard button, but you have used an image element type so:
if(isset($_POST["Download"])){
should be:
if(isset($_POST["Download_x"])){
2) In the download code, the file name is:
"Capital H Health.pdf"
but your link does not contain spaces, it should be:
"CapitalHHealth.pdf"