Trouble opening pdf as email attachment on some ocassions

On some occasions, I have been having trouble opening pdf's as email attachments (When downloading the pdf directly from the webform edit section, the file opens just fine). I cannot determine the conditions that cause this, but it has been happening with the webforms that I have created under the webform version 6.x-3.11. Perhaps webforms created under previous versions are immune to this. The bug also happens on different server environments (I was able to download a pdf attachment when it was sent from my local site as opposed to my online sites for any webform regardless of what version it was created under). I was able to find a fix to my problem based on the following article:

http://drupal.org/node/741466#comment-2752160 where the fix was to simply remove the quotes around the filename variable on the Content-Disposition: parameter during the creation of the pdf email attachment.

My solution was to change the following in line 772 in webform2pdf.module

$message['body'] .= "Content-Disposition: attachment; filename=\"" . $filename . "\"\n\n";

to

$message['body'] .= "Content-Disposition: attachment; filename=" . $filename . "\n\n";