When trying to print from a Business Objects pop up report you need to have a activeX plugin. This makes it so you can export this to PDF and print.
Here is the location for the file you need to change on the Business Objects server:
<Business Objects Home>\Tomcat\webapps\businessobjects\enterprise115\desktoplaunch\viewers\rpt\DHTMLViewer.jsp
Open up the DHTMLViewer.jsp and change the following:
Section iviewer.setPrintMode(CrPrintMode.ACTIVEX); //ACTIVEX by default, or .PDF
Change the ACTIVEX to PDF. This will change how the print button works in the Business Objects pop-up.