I'm really stuck in the part wherein Jasper says there is a last script that I can acquire in order to reach the catwalk. Where can I find this script? And also, when Napolean clogs the gears to seal the drawbridge, how can I unclog it? please help...

I'm really stuck in the part wherein Jasper says there is a last script that I can acquire in order to reach the catwalk. Where can I find this script? And also, when Napolean clogs the gears to seal the drawbridge, how can I unclog it? please help...
Here is a previous discussion on Waterloo and how to remove the thing jamming the drawbridge gear:
http://www.lucasforums.com/showthread.php?t=148786)

And the script to raise the balloon to reach the catwalk requires you to perform 'The day the mailboat finally came'. I think.