My issue is nearly identical to this question. I tried those solution and none worked. But I am using a different Android x86 image. I\'m using the ICS (4.0-RC1) asus_laptop ima
If you can't edit /etc/init.sh or /etc/init.androVM.sh and the error is the read-only file (despite being su) you can just write the following as superuser on the commandline:
setprop net.dns1 10.0.0.138
or any other IP, this is often the local router (capable of DNS). Check your network connection details for getting this IP.
The drawback is, that you have to do this every time, but it is not very time-consuming.