Due to the way Ping works it uses files other than /etc/resolve.conf to find out the address of computer from a name.

After installing Solaris 10 I had this problem. The solution was to put the following into /etc/nsswitch.conf

# You must also set up the /etc/resolv.conf file for DNS name
# server lookup.  See resolv.conf(4).
hosts:      files dns

# Note that IPv4 addresses are searched for in all of the ipnodes databases
# before searching the hosts databases.
ipnodes:   files dns