SNMPv3 - MRTG on Windows monitor Linux router

Monitoring Linux router with 6 100Mb interfaces with MRTG on Windows machine. Now upstream interface card is changed to 1Gbps which need to use 64bit counters. Than I enabled SNMPv3 on the router by this link, all test passed OK.

http://www.fineconnection.com/How_to_install_and_enable_SNMPv3_on_a_linux_system_for_authentication_en_encryption_testing
  
Than I also changed my cfg according to mrtg manual and install SNMP-net and snmp-net-utils packages via PPM.

With this command:

perl mrtg config.cfg --debug=snpo

got this error on interface where SNMPv3 is used:

--snpo: (0) Populate ConfCache for 10.12.0.5:::::3
substr outside of string at mrtg/bin\..\lib\mrtg2/Net_SNMP_util.pm line 1814.
Use of uninitialized value $tmpo in concatenation (.) or string at mrtg/bin\..\lib\mrtg2/Net_SNMP_util.pm line 1815.

Perl: v5.16.3
Mrtg: mrtg-2.17.4
OS: Windows 2003 server

Global cfg section:

EnableIPv6: no
RunAsDaemon: Yes
WorkDir: c:\monitoring\
IconDir: C:\monitoring\mrtg\images
Language: Czech
EnableSnmpV3: yes
options[_]:  growright,bits,unknaszero,nobanner,nolegend

Gigabit ETH interface section:

### Interface 10 >> Descr: 'eth9' | Name: 'eth9' | Ip: '78.108.102.209
Target[10.12.0.5_eth9]: #eth9:[email protected]:::::3
SetEnv[10.12.0.5_eth9]: MRTG_INT_IP="10.10.10.1" MRTG_INT_DESCR="eth9"
MaxBytes[10.12.0.5_eth9]: 1250000000
Title[10.12.0.5_eth9]: eth9   -- Router
PageTop[10.12.0.5_eth9]: <h1>eth9   -- Router</h1>
SnmpOptions[10.12.0.5_eth9]: username=>'guest'

Any ideas?
   
L.