nothing happens when printing/exporting - Crystal Reports

I'm using vb.net 2008 and .NET 3.5.
I have crystal reports in my web application. when the page comes up, the report loads fine and when I use different search criteria, the report still loads fine. My problem is when I click on the crystal print/export buttons, the report disappears and nothing else happens. The normal little pop up box does not come up at all. pop ups are allowed. Does anyone know why the printing and exporting wouldn't be working correctly? I know it used to work and i'm not really sure what, if anything has changed. it just doesn't come up anymore. I'm using crystal 11.5.3700.0.