Please read FAQ to find how to disable passive mode in scripting:
https://winscp.net/eng/docs/faq_script_ini

I'm getting an error with one one FTP (SSL / TLS) site. The error happens via command and and via the GUI, although I can get further via command line. The problem seems to happen as soon as WinScp tries to enter passive mode. I know that -passive enables passive mode on the command line, but I couldn't find a way to disable it.

Any help would be appreciated.

< 2011-09-14 13:13:48.655 Script: Connecting to {FTP Server}:990 ...
. 2011-09-14 13:13:48.655 Connecting to {FTP Server}:990 ...
< 2011-09-14 13:13:48.692 Script: Connected with {FTP Server}:990, negotiating SSL connection...
. 2011-09-14 13:13:48.692 Connected with {FTP Server}:990, negotiating SSL connection...
< 2011-09-14 13:13:48.879 Script: SSL connection established. Waiting for welcome message...
. 2011-09-14 13:13:48.880 SSL connection established. Waiting for welcome message...
< 2011-09-14 13:13:48.912 220-Wildcat! FTP Service (v6.3.453.3 Wed, 14 Sep 2011 14:12:12 -0400) ready.
< 2011-09-14 13:13:48.913 220-Welcome to {Vendor Name} Test's Online FTP server!
< 2011-09-14 13:13:48.913 220-
< 2011-09-14 13:13:48.913 220-This is an intranet-based FTP server primarily available to WIN Server
< 2011-09-14 13:13:48.913 220-customers. Public file directories are available to the general public
< 2011-09-14 13:13:48.913 220-(anonymous logins). You must have a valid user id and password to gain
< 2011-09-14 13:13:48.947 220-access to the private file areas. WEB users can login using a url
< 2011-09-14 13:13:48.947 220-like: ftp://username:password@domain.com/
< 2011-09-14 13:13:48.947 220
> 2011-09-14 13:13:48.947 USER BSG
< 2011-09-14 13:13:48.989 331 Password required for BSG.
> 2011-09-14 13:13:48.989 PASS ********
< 2011-09-14 13:13:49.050 230-Wildcat! FTP Server v6.3.453.3 node: 2
< 2011-09-14 13:13:49.288 230 User {My user account} logged in.
> 2011-09-14 13:13:49.288 SYST
< 2011-09-14 13:13:49.328 215 WIN32 Type: L8 Wildcat
> 2011-09-14 13:13:49.328 FEAT
< 2011-09-14 13:13:49.372 211-Extensions supported
< 2011-09-14 13:13:49.604 CLNT
< 2011-09-14 13:13:49.604 SIZE
< 2011-09-14 13:13:49.605 MDTM
< 2011-09-14 13:13:49.605 REST STREAM
< 2011-09-14 13:13:49.605 MLST size*;type*;perm*;create*;modify*;
< 2011-09-14 13:13:49.605 AUTH SSL;TLS-P;TLS-C;
< 2011-09-14 13:13:49.605 PBSZ
< 2011-09-14 13:13:49.605 PROT C;P
< 2011-09-14 13:13:49.605 211 END
> 2011-09-14 13:13:49.605 PBSZ 0
< 2011-09-14 13:13:49.643 200 PBSZ=0, streaming TLS, no buffer.
> 2011-09-14 13:13:49.643 PROT P
< 2011-09-14 13:13:49.684 200 Ok, data will be protected.
< 2011-09-14 13:13:49.684 Script: Connected
. 2011-09-14 13:13:49.685 Connected
. 2011-09-14 13:13:49.685 Got reply 1 to the command 1
. 2011-09-14 13:13:49.685 Doing startup conversation with host.
< 2011-09-14 13:13:49.685 Script: Starting the session...
> 2011-09-14 13:13:49.687 PWD
< 2011-09-14 13:13:49.724 257 "/{Remote Directory}" is current directory.
. 2011-09-14 13:13:49.724 Got reply 1 to the command 16
< 2011-09-14 13:13:49.724 Script: Reading remote directory...
. 2011-09-14 13:13:49.724 Changing directory to "/{Remote Directory}".
> 2011-09-14 13:13:49.724 CWD /{Remote Directory}
< 2011-09-14 13:13:49.762 250 CWD command successful.
. 2011-09-14 13:13:49.762 Got reply 1 to the command 16
. 2011-09-14 13:13:49.762 Getting current directory name.
> 2011-09-14 13:13:49.762 PWD
< 2011-09-14 13:13:49.800 257 "/{Remote Directory}" is current directory.
. 2011-09-14 13:13:49.800 Got reply 1 to the command 16
. 2011-09-14 13:13:49.800 Startup conversation with host finished.
< 2011-09-14 13:13:49.800 Script: Session started.
. 2011-09-14 13:13:49.801 File: "\{File I'm Uploading}"
. 2011-09-14 13:13:49.805 Copying "\{File I'm Uploading}" to remote directory started.
. 2011-09-14 13:13:49.805 Binary transfer mode selected.
. 2011-09-14 13:13:49.805 Starting upload of \{File I'm Uploading}
> 2011-09-14 13:13:49.805 TYPE A
< 2011-09-14 13:13:49.843 200 Type set to A.
> 2011-09-14 13:13:49.843 PASV
< 2011-09-14 13:13:49.887 227 Entering Passive Mode (159,240,9,112,15,225)
> 2011-09-14 13:13:49.887 LIST
. 2011-09-14 13:14:04.570 Timeout detected.
. 2011-09-14 13:14:04.571 Copying files to remote side failed.
. 2011-09-14 13:14:04.571 Got reply 1004 to the command 4
. 2011-09-14 13:14:04.571 Connection was lost, asking what to do.
. 2011-09-14 13:14:04.571 Asking user:
. 2011-09-14 13:14:04.571 Lost connection. ("Timeout detected.","Copying files to remote side failed.","Entering Passive Mode (159,240,9,112,15,225)")