Unable to get "live" print button in print dialog window when trying to print from browser; no problem with other sources.

[Bluemax_36]

I have a PSC 1200 series printer (all-in-one machine). Until recently it worked very well. If I try to print e-mail messages or documents, it continues to work very well. The problem is when I try to print a page from my browser (Firefox). I can get a good print preview. When I select "print" on the pull-down file menu, I see the normal dialog box. At the bottom of the dialog box there are two buttons, "Cancel" and "Print." When I'm trying to print pages from the browser, the "Print" button is ghosted and not live, so I'm unable to press it to complete the printer dialog box.