Here is a process list and strace to smbclient and tar. You can see that
is stalled at some opening of the file.
I modified share name and file name for security reasons.

regards,
gregor

19432 ?        S      0:00 /bin/sh /usr/sbin/amdump tape
19442 ?        S      0:20 /usr/libexec/amanda/driver tape
19443 ?        S     21:31 taper tape
19444 ?        S     69:20 dumper0 tape
19445 ?        S      5:36 dumper1 tape
19446 ?        S      3:26 dumper2 tape
19447 ?        S     17:10 taper tape
24836 ?        S      0:00 /usr/libexec/amanda/sendbackup
24838 ?        S      0:00 /bin/gzip --best
26743 ?        S      0:01 /usr/libexec/amanda/sendbackup
26761 ?        S      0:00 pickup -l -t fifo -u
26747 ?        S      0:00 sed -e s/^\.//
26746 ?        S      0:00 /bin/tar -tf -
26745 ?        S      0:00 sh -c /bin/tar -tf - 2>/dev/null | sed -e
's/^\.//'
26744 ?        S      0:07 smbclient \\server\sharename -U username -E
-d0 -Tqca
26778 pts/15   R      0:00 ps ax


[root@backup root]# strace -p 26744
Process 26744 attached - interrupt to quit
write(2, "NT_STATUS_ACCESS_DENIED opening "..., 134 <unfinished ...>
Process 26744 detached


[root@backup root]# strace -p 26745
Process 26745 attached - interrupt to quit
wait4(-1,
Process 26745 detached

[root@backup root]# strace -p 26746
Process 26746 attached - interrupt to quit
read(0,  <unfinished ...>
Process 26746 detached

[root@backup root]# strace -p 26747
Process 26747 attached - interrupt to quit
read(0,  <unfinished ...>
Process 26747 detached

[root@backup root]# strace -p 26743
Process 26743 attached - interrupt to quit
read(0,  <unfinished ...>
Process 26743 detached

[root@backup root]# strace -p 24836
Process 24836 attached - interrupt to quit
write(2, "filename.txt (\\Data\\"..., 50 <unfinished ...>
Process 24836 detached