Flesh out the netconf dialog a bit by having it display an error, and add a stub for sceNetApctlDisconnect.

The latter fixes a hang in Phantasy Star Portable 2 when trying to connect to PSN/online multiplayer, and the former prevents a hang in the Monster Hunter games when trying to download DLC.

![Screenshot 01](http://i.minus.com/iBaC9DEv3WTFv.jpg)

It needs a bit of work before it looks exactly like the PSP's Network Connection dialog, but it's a good start.