I can't Set Table Variables

I can't Set Table Variables
My command is:
snmpwalk -v 2c -c private localhost .1.3.6.1.2.1.4.21.1.7
The result is:
RFC1213-MIB::ipRouteNextHop.0.0.0.0=IpAddress: 192.168.101.12
RFC1213-MIB::ipRouteNextHop.169.254.0.0=IpAddress: 0.0.0.0
RFC1213-MIB::ipRouteNextHop.192.168.101.0=IpAdress: 0.0.0.0
but  when I exec command:
snmpset -v 2c -c private localhost .1.3.6.1.2.1.4.21.1.7.0.0.0.0 a 192.168.101.35
The result is:
error in packet.
Reason:wrongType (the set datatype does not match the data type the agent expects
Failed object:RFC1213-MIB::ipRouteNextHop.0.0.0.0
private is a community that can be set。I have use this community to set sysName,sysLocation,sysContact successfully，but I can't set the table variables.
what's wrong with it?Please help me!Thank you !