I'm gonna go out on a whim here and see if I can get away with pretty much telling you what to do. So much for finding shit out for yourself ¬¬
Right. The script, basically, consideres you as a l33t h4x0r once you've got 4000 votes. When you make a vote, obviously, the required vote count goes down. Now, when you get to it and you see 4000 votes, make one or two till you get 3998 left. 3998 is a fairly distinctive number, yes?
... now, imagine. How does this script know how many votes you need? Does it use... mySQL? Nah that'd be stupid. So what other temporary storage methods are there? Something usually used when you visit a site and they wanna keep track of who you are, perhaps?
...
...
...
Then once... you've figured this out, think of how you'd usually see your own information. You can find it in a file, or there're certain commands. Once you've seen it, you'll notice a certain number that should look familiar... somewhere around the 39** mark?

Then, once you know where it is and you know there're ways to view it, look into ways of modifying it.
... I'll give you this last bit because there's no way you'll get it if I just hint at it. In this info you'll find % characters. Where you'll be using this, it won't be treated as raw text. I pointed you to a hex/ASCII site (try
http://asciitable.com) so you can see the other ways % can be represented.
... if I told you anymore than this, I'd practically be giving it to you.