LowID means simply that you are behind a firewall, or for whatever reason your aMule ports are inaccessible from the outside. With LowID you can still upload and download.
If you want to open all ports aMule need, open(assuming default setup):
1) (tcp) 4662
2) (udp) 4665
3) (udp) 4672
If you want to know more about ports I suggest you search the forums, there are many posts about that.