Cannot drag and drop in download of big files

I have used SmartFTP for years, but within past month or so, I cannot drag and drop a file larger than 1 MB to download from our server to my client. I get message sequence below. I can download the files using the ftp address or by supplying a URL and entering it into my browser... that works. But what an extra hassle.

I've changed connection from Active to Passive, and extended time out in Settings > Connections.

Here's the message sequence I get as the transfer fails when I drag the file to the local directory:

[06:23:02] Opening data connection to Port: 48682
[06:23:02] RETR
[06:23:04] 0 bytes transferred. (0 bytes/s) (00:00:02)
[06:23:04] 150 Opening BINARY mode data connection for (34493337 Bytes).
[06:23:04] 426 Data connection closed, file transfer aborted.
[06:23:04] MDTM
[06:23:05] 213 20051031030018
[06:23:05] Transfer failed.

Can anyone help me?