What are the permissions of your files in /opt/zimbra/jetty-6.1.5/etc/?
I've attached a listing of mine for comparison in case it's a permissions problem (This is from 5.0.6 FOSS edition on Debian).
Code:
zimbra@utopia:~$ ls -l /opt/zimbra/jetty/etc/
total 132
-r--r--r-- 1 zimbra zimbra 5055 May 23 04:42 jetty-setuid.xml
-r--r----- 1 zimbra zimbra 836 Jun 1 08:58 jetty.properties
-r--r--r-- 1 zimbra zimbra 1152 May 23 04:42 jetty.properties.in
-r--r----- 1 zimbra zimbra 14759 Jun 1 08:58 jetty.xml
-rw------- 1 zimbra zimbra 14518 Jun 1 08:58 jetty.xml.in
-r--r--r-- 1 zimbra zimbra 289 May 23 04:42 jettyrc
-rw-r--r-- 1 root root 1461 May 28 05:11 keystore
-r-xr-xr-x 1 zimbra zimbra 10283 May 23 04:42 service.web.xml.in
-r--r--r-- 1 zimbra zimbra 2973 May 23 04:42 start.config
-r--r--r-- 1 zimbra zimbra 27587 May 23 04:42 webdefault.xml
-rw------- 1 zimbra zimbra 12354 Jun 1 08:58 zimbra.web.xml.in
-rw------- 1 zimbra zimbra 12361 Jun 1 08:58 zimbraAdmin.web.xml.in
Note that zmtlsctl is a bash script located in /opt/zimbra/bin/ so if the above doesn't help, perhaps looking at what the script does might give a clue as to why it's failing....