FTP --> .ZIP file copying problem or bug

When I try to copy a file on an FTP server in to a .zip archive on my local machine the copy dialog window opens but the file never gets transfered and it can never be closed or aborted until I quit Opus completely.

It seem this is a bug?

It works normally for me using U

Presumably downloading to a normal directory, instead of a Zip, does work?

Does copying a file from a local directory into a Zip also work?

Is there any information in the FTP log? (Tools | Output Window)

Tried toggling the PASV option for the site in Preferences? (Probably won't help but worth a quick try.)

Which FTP server software is it?

Sorry, I should have made myself a little clearer and added that this problem seems to randomnly occur for me. I'm not sure exactly when and how but every now and again it happens. The only thing I can think of is that the problem is due to a connection time-out or something.