Forums Scripts & Popups FTP Upload

I want to try to connect to a FTP and upload something with a mIRC-script, the problem: it doesn't work.
I can connect, I can enter USER/PASS-command, but from that step, I don't know what to do...
I tried to use the STOR-command, but I don't know how to use it correct.
Someone got an idea?
If I trie the STOR-command, I get error: <- 425 Unable to build data connection: Invalid argument

Because I don't know how to transmit the file through FTP.

I think I first should open PASV connection for the file transfer, and connecting to that IP+PORT, but then I don't know anymore.

There's a great FTP script here: http://www.mircscripts.org/comments.php?cid=2520

If you don't want to use that, just look through it and check out how it works

Thanks man