FTP attempts causes Internet Connection loss

Why is it that whenever I attempt an FTP server connection, I *sometimes*
lose my Internet
Connection entirely?
I then have to physically disconnect the power cord to my router (connected
to DSL) and then re-connect, to reset that lost Internet Connection!

This doesn`t occur every attempt, only if it can`t connect to the FTP
server relatively quickly, or then it seems to just hang.... and then the
Internet Connection itself is lost!

Is there something I can do to prevent this Internet Connection loss or is
this normal?

Thanks in advance, Matt