it is very hard to print content within a scrollpane, because of the viewable amount of space. What I do to get around this is create something like a print preview mode.
If the user hits print, I then take them to another frame that shows whatever movie clip is the scrollPanes content, by itself. That way the whole clip is shown on the stage and you can print it. I also create a close button, so when pressed, it will jump back to the original frame with the scrollpane.
This is a simple algorhythm of what i do:
1. Move to another frame with no scrollPane
2. Create Holder_mc at 0,0 of new frame
3. Attach Content clip to Holder_mc
4. Make visible "CLOSE PRINT" button (which will take you back after printing)
5. Set boolean variable _isPrintPreview to true
Something like that should work okay for you.