UNIX for Dummies Questions & Answers

Hello All,
I have installed cacti and I have Nan values on created graph.
I really appreciate any help.
I have done the following:

1. Linux Ubuntu 12.04.2 LTS 64 bits
2. apt-get install cacti // the cacti Version 0.8.7i was installed
3. Accessed "http://MyIP/cacti/index.php"
4. Set SNMP Version: 2c
SNMP Community: public
Poller Type: spine
5. Created new Device "QA" with SNMP v2 and SNMP Community: public
6. Console -> New Graph:
Host: QA
Create: SNMP Generic OID template
Data Source Type: GUAGE
Custom Data OID: .1.3.6.1.6.3.12.1.3.1.6.105.110.116.101.114.110.97.108.48
7. Console -> Management -> Graph Tree -> Add QA host.

[Result]
My Graph is empty and shows Nan Value

[Investigation]
1. QA machine is also Linux Ubuntu 12.04.2 LTS 64 bits with snmpd installed. (apt-get install snmpd )
2. snmpget -v 2c -c public QA_IP .1.3.6.1.6.3.12.1.3.1.6.105.110.116.101.114.110.97.108.48 is returning value "5"
3. tcpdump on QA Machine has output:
12:37:56.293812 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 83)
dev-qa19.snmp > 192.168.13.87.36824: [bad udp cksum 0x9b12 -> 0xa535!] { SNMPv2c { GetResponse(40) R=1122116738 S:12.1.3.1.6.105.110.116.101.114.110.97.108.48=5 } }
4. Date and Time are identical on both machines
5. rrdtool fetch qa_snmp_oid_21.rrd AVERAGE displays only "nan" values
6. ufw are stopped on both machines
7. /var/lib/cacti/rra has 777 permissions.


If you have any Ideas please share them with me.

Thank You in Advance, Best Regards