Unable to obtain z/VM server directory listing

[Mark Cibula]

After successful login to a z/VM 530 (or higher level) FTP server, no directory listing is obtained. This error occurs regardless of the list format setting of the /VM host (which can be either 'VM' or 'UNIX') or of the client Site Manager "Advanced" tab 'Servertype' setting (both 'z/VM' or 'default (Autodetect)' yield the same failure. A log showing this error follows:

14:22:39 Trace: CControlSocket::DoClose(64)
14:22:39 Status: Connecting to 9.xx.xx.xx:221...
14:22:39 Status: Connection established, waiting for welcome message...
14:22:39 Trace: CFtpControlSocket::OnReceive()
14:22:39 Response: 220-FTP BANNER for TCPIP04.VMxxx.xxxxxxxx.xxx.xxx
14:22:39 Trace: CFtpControlSocket::OnReceive()
14:22:39 Response: FTPSRV04 IBM VM Level 530 at VMT1.xxxxxxxx.xxx.xxx, 14:21:49 EDT MONDAY 2009-06-01
14:22:39 Trace: CFtpControlSocket::OnReceive()
14:22:39 Response: 220 Connection will close if idle for more than 5 minutes.
14:22:39 Trace: CFtpControlSocket::SendNextCommand()
14:22:39 Command: USER TCPMNT04
14:22:39 Trace: CFtpControlSocket::OnReceive()
14:22:39 Response: 331 Send password please.
14:22:39 Trace: CFtpControlSocket::SendNextCommand()
14:22:39 Command: PASS
14:22:39 Trace: CFtpControlSocket::OnReceive()
14:22:39 Response: 230-TCPMNT04 logged in; working directory = TCPMNT04 191 (ReadOnly)
14:22:39 Response: 230 write access currently unavailable
14:22:39 Status: Connected
14:22:39 Trace: CFtpControlSocket::ResetOperation(0)
14:22:39 Trace: CControlSocket::ResetOperation(0)
14:22:39 Trace: CFileZillaEnginePrivate::ResetOperation(0)
14:22:39 Status: Retrieving directory listing...
14:22:39 Trace: CFtpControlSocket::SendNextCommand()
14:22:39 Trace: CFtpControlSocket::ChangeDirSend()
14:22:39 Command: PWD
14:22:39 Trace: CFtpControlSocket::OnReceive()
14:22:39 Response: 257 "TCPMNT04.191" is working directory (ReadOnly)
14:22:39 Trace: ControlSocket.cpp(361): Failed to parse returned path. caller=0p152b050
14:22:39 Trace: CFtpControlSocket::ResetOperation(2)
14:22:39 Trace: CControlSocket::ResetOperation(2)
14:22:39 Trace: CFtpControlSocket::ParseSubcommandResult(2)
14:22:39 Trace: CFtpControlSocket::ListSubcommandResult()
14:22:39 Trace: state = 1
14:22:39 Trace: CFtpControlSocket::ResetOperation(2)
14:22:39 Trace: CControlSocket::ResetOperation(2)
14:22:39 Error: Failed to retrieve directory listing
14:22:39 Trace: CFileZillaEnginePrivate::ResetOperation(2)

The transfer type is FTP (no SSL/TLS security involved).
No 'Default remote directory' is specified with the Site Manager 'Advanced' box.

After having specified such default remote directory as '/tcpmnt04.191', the described error does not occur (and, the leading slash (/) is critical in this regard; in fact, specifying a single '/' as the remote default directory appears to alleviate this problem.

The leading '/' is not part of the z/VM file system
structure, and seemingly should not be required to be specified as a remote directory default, especially for the case when 'z/VM' (specifically) is designated as the (remote) servertype.