The previous version that I know worked is 1932. However, when I installed 1932 over 1936 it still wouldn't work. I had to uninstall FlashFXP and then install 1932 and it worked. See below. I am connecting to a NAS drive so I believe it is using OpenSSH.
FlashFXP 4.3.0 (build 1932)
Support Forums
http://forum.flashfxp.com
Winsock 2.2 -- OpenSSL 1.0.1d 5 Feb 2013
[R] Connecting to 192.168.2.10 -> IP=192.168.2.10 PORT=****
[R] Connected to 192.168.2.10
[R] Host key algorithm ssh-RSA, size 2048 bits.
[R] Fingerprint (MD5): e9:ac:d2:61:a3:0b:22:e7:d3:f8:a9:21:05:fa:dc:24
[R] Key exchange: diffie-hellman-group14-sha1. Session encryption: aes256-ctr, MAC: hmac-sha1, compression: none.
[R] Auth Type: Password
[R] Authentication succeeded
[R] SSH Connection open
[R] Connection established with OpenSSH_5.8p1-hpn13v11 (SFTP v3)
[R] SFTP Connection Ready
[R] Retrieving file list...
[R] List Complete: 761 bytes in 0.03 second (0.7 KB/s)