Warning: unlink

Warning: unlink(C:\%PATHTOSITE%\transfers\new-clients) [function.unlink]: Permission denied in C:\%PATHTOSITE%\WA_DigitalFilePro\HelperPHP.php on line 718

This appears to be a permissions error, but the Anonymous User has modify permission on the folder and can successfully upload, and the file does delete.

The part of the code it is failing on is:
if(file_exists($path) && is_writable($fullPath)){
unlink($fullPath);
$result = TRUE;

specifically the unlink($fullPath) line.

I'm not sure what the error pertains to or what might be causing it.

try adding a chmod() command before the unlink command to change the permissions on the file being deleted to full :

chmod($fullPath, 0777);
unlink($fullPath);