Side note: Argh. My eyes. Some spaces in that first post, please.
First: You'll notice that there's a big fat warning in the config file that says: Please do not edit me while usbnet is on...
. Which explains why it's confused as to what to do when you use the usbNetwork command. But that still shouldn't break the switch back to usbms, unless notepad++ did something horribly wrong to the file... (or you made the mistake of switching the SSHD only mode to true while usbnet was enabled).
Just restart your Kindle, provided you didn't enable the auto feature, everything should be fine. (ie. in usbms mode). (Also, you'll need the latest version of the hack for the auto feature not to mess up the switch back to usbms anyway).
EDIT: Which you did... So, like enn said, use a proper OS, or install whatever windows needs to handle this ethernet over usb device. (Can't help you there, don't use Windows). But, since you enabled the WIFI mode, the SSHD will ask for a passwd. So, unless you already setup pubkey auth, or know the root password, you're kinda screwed on the ssh front. Or, if you didn't completely mess up the config file, try to telnet over usb.
As for the exec private command, it's a fluke when your Kindle actually still has the testing scripts needed for that to work, so, not surprising that it doesn't do a thing
And, no, an official update won't touch anything pertaining to the hacks. The only thing you could do that would disable (not uninstall!) the hack is a reset to factory defaults.