Both CMU SNMP 3.5 and UCD SNMP does not work on 2.2 kernels. The kernels have different layout of /proc/net/dev file, which causes SNMP-daemon to report zero traffic on the network interface in one direction (I don't remember whether it is outgoing or incoming traffic). For me it was fixed by installing CMU SNMP version 3.6. The modified .spec file for the 3.6 can be downloaded at http://www.fi.muni.cz/~kas/cmu-snmp.spec.
Thank you for you suggestion. It has been passed on to a developer.
The most recent version of the ucd-snmp package (3.6.1) does work with the 2.2 kernel.
Fixed in ucd-snmp-3.6.1. Thanks for the pointer.