Issues with network proxy - cant ftp outside of network is there any hope?

OK, I am having real trouble FTPing outside my network. I got it to work on Mozilla, but as you may already know, you can't upload files in Mozilla. I have tried various ftp clients for my windows box but nothing works. Now, what I thought I'd try, is create a PHP program to put files to my server instead of using clients and browsers (IE doesn't work either btw). But I knew it wouldn't work inside my network. So I FTP'd the php file to the server I am trying to get to, through a computer outside the network. Then when I try uploading a file, it says no such file exists on that server. So basically, what I would like to know is why the script doesn't see the file I am trying to upload as a local file. Is it cos local files are only deemed local if they are stored on the same server as the php script? PLz help, this is giving me headaches!

Thanks, fire