After ASCII upload ... "Connection closed. Server timeo

Hello,

I have DSL, use SFTP v1.0.982, and am trying to figure out why (suddenly) my FTP uploads succeed only if:

1. my file size is 1452 bytes or smaller
or
2. I set the "total" upload speed to 1 KB/s

Essentially the same thing happens when I upload using Macromedia's FTP client, so this is NOT limited to SFTP. I use Win2000 Pro, and did a bunch of Windows updates recently that have me worried.

If I don't do #1 or 2 above, the SFTP log shows these entries:

Estimated Compression Ratio of 'F:DevBBCsiteWWWcontact-us.html': 27.32% (3.51 KB/12.8 KB)
PASV
227 Entering Passive Mode (216,24,27,80,219,101).
Opening data connection IP: 216,24,27,80,219,101 PORT: 56165.
STOR contact-us.html
150 Opening ASCII mode data connection for contact-us.html
13168 bytes sent successfully. (12.86 KB/s) (00:00:01).
Connection closed. Server timeout.
PASV
Connection closed. Server timeout.
Command aborted. Server timeout.

Anyone have an idea where I can check to fix this?

Thanks in advance,
Ken Lundberg