Display a Hyperlink in IE 8 and 7 not generating pdf

I am trying to pass a compiled URL that generates a .pdf within a workflow. The string works great in IE 9, Firefox and Chrome, but I cannot seem to get the image to generate in Internet Explorer 8 or 7 (It's an IT thing, pardon). The URL looks something like:

 http://<servername>/Geocortex/Essentials/Waukesha/REST/sites/ROD/printtemplates/15/print?bbox=2500875.67999999%2C355131.619947776%2C2503562.29013054%2C357866.539947778&bboxSR=&targetSR=&time=&graphics=&layers=&layerDefinitions=&opacity=&mapServiceOptions=&featureLayerOptions=&scale=2400&dpi=300&outputFormat=Pdf&tf_TOWN=06&tf_RANGE=20&tf_SECTNO=22&tf_QUADRANT=SW%201/4&f=file#

In IE 8 or 7, I get a progress bar for a few seconds then just a white page, no .pdf. I've uninstalled/reinstalled adobe and also tried unchecking the "Display PDF in browser" in Acrobat Reader, but those did not fix the issue.

Another IE gripe is how does one force a cache-clearing on the client? After our upgrade to 3.5/1.8 this weekend, we had many users complain that they were seeing an initialization error that was really just a cached page. 

Thanks.