[AGENT++] SNMP++ Get Error, SNMP: Variable does not exist

[amine mohamed]

HI,
i'm trying to understand how to create an snmp agent .so, i compiled two projects examples snmpget.exe and amb_atm.exe (example with amb_atm mib)
so when i start the programs i get the error  "SNMP++ Get Error, SNMP: Variable does not exist" almost all the time exept for 1.3.6.1.2.1.1.1.0 and 1.3.6.1.2.1.37.1.13.0 
so what is the problem ? do i need to add anything to the registry or what ? i test my program with oid from files atm_mib.h ,agentpp_test_mib.h  and agentpp_notifytest_mib.h  ,is what i do true? and please what is the difference between the three of these files ?

i try to understands these examples before i begin create my agent witch i have generated his mib .h and mib .cpp 

thanks for your help