SIOCADDMULTI failed for device tap0

In general, the TCPIP setup works, and I can ping the outside world from the guest OS.  However, I get this error when trying to FTP from Windows to the guest OS (either get or put).   Any help would be appreciated. Thanks.
 

 Extracts from Hercules log:
 

 21:34:58 HHC01413I Hercules version 4.2.1.9826-SDL-g9b5cbe3d (4.2.1.9826)
 21:34:58 HHC01414I (C) Copyright 1999-2019 by Roger Bowler, Jan Jaeger, and others
 21:34:58 HHC01417I ** The SoftDevLabs version of Hercules **
 21:34:58 HHC01415I Build date: Sep 10 2019 at 11:14:57
 21:34:58 HHC01417I Built with: Microsoft Visual Studio 2008 (MSVC 150030729 1)
 21:34:58 HHC01417I Build type: Windows MSVC AMD64 host architecture build
 

 21:34:58 HHC00018I Hercules is running in elevated mode
 ...
 21:34:58 HHC04100I TunTap64.dll version 3.7.0.5226 initiated
 21:34:59 HHC04100I TunTap64.dll version 3.7.0.5226 initiated
 21:34:59 HHC00901I 0:0E20 LCS: Interface tap0, type TAP opened
 21:34:59 HHC00921I CTC: lcs device port 00: tuntap Multicast assist enabled
 21:34:59 HHC00935I CTC: lcs device port 00: manual Checksum Offload enabled
 21:34:59 HHC00901I 0:0E22 CTCI: Interface tun0, type TUN opened
 ...
 22:05:25 HHC00942I CTC: lcs device tap0 using mac 02:00:5E:A8:01:65
 22:05:25 HHC00941E CTC: ioctl SIOCADDMULTI failed for device tap0: Cannot create a file when that file already exists.
 22:05:25 HHC00007I Previous message from function 'LCS_DoMulticast' at ctc_lcs.c(1751)
 22:17:27 HHC00942I CTC: lcs device tap0 using mac 02:00:5E:A8:01:65
 22:17:27 HHC00941E CTC: ioctl SIOCADDMULTI failed for device tap0: Cannot create a file when that file already exists.
 
 22:17:27 HHC00007I Previous message from function 'LCS_DoMulticast' at ctc_lcs.c(1751)
 

 Hercules config file statement:
 

 0E20.2 LCS -n 192.168.1.101 192.168.1.161

 

 Guest OS statements:
 

 DEVICE LCS1   LCS           E20
 LINK ETH1  ETHERNET  0  LCS1
 HOME
 192.168.1.161      ETH1
 

 BEGINRoutes
 ROUTE 192.168.1.0    255.255.255.0   =         ETH1   MTU DEFAULTSIZE
 ROUTE DEFAULT        192.168.1.1               ETH1   MTU DEFAULTSIZE
 ENDRoutes
 

 START LCS1