HEEEEELP...tbp repository service

I'm trying to create a new repository service but i´m having some trouble. I want to make a service that automatically runs when i upload a new document and it changes the validto date of the doc to three months ahead from the current date. This is the code that i've built using some examples found in the forums but it's not working at all:

http://pastebin.com/m5fec70b5

Any help, please. I'm desperate!