SFTP upload works, download disconnects

I set up an SSH server on Ubuntu with OpenSSH and SFTP using MySecureShell. I can connect to it just fine and navigate and even upload files, but the instant I try to download anything, it disconnects. The same server works just fine using Bitvise Tunnelier. I set FlashFXP to enable disk based loggin, but I cn't find the file anywhere (using Vista Home).

Try turning off compression.