In case you are faced with this error when you attempt to list shared on Windows systems and when running strace smbclient -L //192.168.0.10 -U'root%SECRET' -vvvv:

stat("/usr/lib64/samba/en_US.UTF-8.msg", 0x7fffb902c980) = -1 ENOENT (No such file or directory)
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), …}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fe86235c000
write(1, "Connection to 192.168.0.10 faile"…, 66Connection to 192.168.0.10 failed (Error NT_STATUS_ACCESS_DENIED)
) = 66
exit_group(1)                           = ?
[root@mbpc ~]# smbclient -L //192.168.0.17 -U'root%SECRET' -vvvv
Connection to 192.168.0.10 failed (Error NT_STATUS_UNSUCCESSFUL)
[root@mbpc ~]#

Here's some information that can help you resolve this quickly.

This solution is now posted on the following page on Networking: Sharing folders between Windows and Linux using Samba on Page 3 near the bottom.

Cheers,
TK