cfgmaker snmpv3 available, but using v1/v2c

Just starting out with mrtg and I'm trying to use snmp v3 with cfgmaker 
but it seems to be falling back to v1/v2c, v3 seems to be set up 
correctly on the router and I can snmpwalk with my roUser.
Any ideas why this isn't working?

# cfgmaker  --enablesnmpV3 --username  roUser --authprotocol=MD5 
--authpassword  xxxxxxxx --privprotocol=DES -privpassword  xxxxxxxx 
--contextengineid=0 192.168.200.245
--base: SNMP V3 libraries found, SNMP V3 enabled.
--base: snmpv3 available, but using v1/v2c for [email protected]:
--base: Get Device Info on [email protected]:
Use of uninitialized value $DevInfo{"sysObjectID"} in concatenation (.) 
or string at /usr/local/bin/cfgmaker line 1003.
Use of uninitialized value in pattern match (m//) at 
/usr/local/bin/cfgmaker line 1005.
Use of uninitialized value in pattern match (m//) at 
/usr/local/bin/cfgmaker line 1005.
Use of uninitialized value in pattern match (m//) at 
/usr/local/bin/cfgmaker line 1005.
.. snip
--base: Vendor Id: Unknown Vendor -
--base: Populating confcache
SNMPWALK Problem for ifName on [email protected]::::::v4only: 
Received noSuchName(2) error-status at error-index 1 at 
/usr/local/bin/cfgmaker line 152
--base: Get Interface Info
Use of uninitialized value $descr in pattern match (m//) at 
/usr/local/bin/cfgmaker line 192.
Use of uninitialized value $descr in pattern match (m//) at 
/usr/local/bin/cfgmaker line 192.
--base: Walking ifIndex
--base: Walking ifType
--base: Walking ifAdminStatus
--base: Walking ifOperStatus
--base: Walking ifMtu
--base: Walking ifSpeed
Use of uninitialized value $comment_sysdescr in substitution (s///) at 
/usr/local/bin/cfgmaker line 379.
Use of uninitialized value $sysname in concatenation (.) or string at 
/usr/local/bin/cfgmaker line 412.
Use of uninitialized value $comment_sysdescr in concatenation (.) or 
string at /usr/local/bin/cfgmaker line 412.
Use of uninitialized value $syscontact in concatenation (.) or string at 
/usr/local/bin/cfgmaker line 412.
Use of uninitialized value $syslocation in concatenation (.) or string 
at /usr/local/bin/cfgmaker line 412.
# Created by
# /usr/local/bin/cfgmaker --enablesnmpV3 --username roUser 
--authprotocol=MD5 --authpassword xxxxxxxx --privprotocol=DES 
-privpassword xxxxxxxx --contextengineid=0 192.168.200.245


### Global Config Options

#  for UNIX
# WorkDir: /home/http/mrtg

#  or for NT
# WorkDir: c:\mrtgdata

### Global Defaults

#  to get bits instead of bytes and graphs growing to the right
# Options[_]: growright, bits

EnableIPv6: no

######################################################################
# System:
# Description:
# Contact:
# Location:
######################################################################


enablesnmpv3: yes