You get the same error in all of your browsers?

Do you know whether the label is a PDF document? That's fairly common because it provides the most stable layout compared with a regular web page.

If it is a PDF and you are using the Adobe Acrobat viewer, there is a hidden floating control bar with a print icon that appears as you move the mouse pointer toward the bottom of the document. Or if you press the Esc key, then a normal toolbar appears above the PDF.

Not sure whether I'm going in the right direction with this...

In the Edit drop down menu, hit convert to snapshot. It is now a picture and you simply drop it into a blank Word doc. Comes out exactly as it should.

Hmm, convert to snapshot? Is that in Firefox using an add-on or in a completely different program?

I had saved the usps label in the Adobe Reader file. When opening any of these files there is an Edit menu in the heading. The Snapshot feature is in the drop down menu under Edit. When you click on Snapshot, the pointer forms a plus sign and you are able to scan the pic with the mouse. You can scan any portion of the pic or all of it by starting in a corner with the plus sign, then left click to scan the pic as you would for any object you wish to copy. It then automatically is placed on the clipboard and you can drop it anywhere.