Oh wow you didn't say everything that you did to cause this problem . If u read cm10 isn't ready for use nor ready for flashing . But if u was to read many had the same problem and u wanted to try it out . I hate to tell you this but u may need to downgrade and use the lg tool to update to zve again . Reason for this is your settings on the phone has been changed .
The custom rom changes the settings to run the cm10. Now you chose to jump back to gingerbread . Now gingerbread doesn't have the same settings . So this is why the lg tool and lgpnst isn't working cause u need special tools to help the phone back to the carrier settings .
******NOW TO FIX FOLLOW AND ANY PROBLEMS POST BACK ******.
[GUIDES] Downgrade ZVD/ZVC To ZVB/Emer. PB Recovery - Android Forums