ftp transfer

I am trying to write some code which will upload and download a file from an ftp site. I've written some code which works on windows 98 and windows 95 using a dial-up connection. however, a pc installed this code and tried to run it on an NT machine with a permanent connection. Since trying to run the code he has been unable to access the internet although he can send/receive e-mails. I have attached the code which gets the ftp file (the sendftp operates in the same way). Does anyone have any idea why this may have happened or safer ways (cross platform) of uploading and downloading files to and from an ftp site.

Thanks for your help
Paul