Sounds like you've had a fairly rough go of it…
So, a couple things.
1. Can you still access and use your phone like normal?
2. Can you mount the SD card via USB from your computer?
If so, you may just need to redo step 4 from the
http://androidforums.com/optimus-v-all-things-root/380801-guide-rooting-without-computer.html guide.
Things to check:
1. does "su" work - open up terminal emulator (or download it from the market if you don't have it). type "su" (without the quotes) at the prompt and hit enter. This should cause the command prompt to turn from "$" to "#". su is short for super user and means you have root access to your phone. try typing something like "ls" just to verify that it outputs. If this is all good, then exit out of it. If this isn't working for some reason, you don't really have root on your phone and you'll need to resolve that first.
2. Locate a recovery that works for your s-screen phone and download it to your computer. You are looking for an image file (.img) not a zip file. There is information for that here:
https://github.com/inferiorhumanorgans/android_device_lge_thunderc/wiki/Binary under the "For Optimus V" section. Once you've chosen the appropriate recovery and downloaded it, change it's name to "vrecovery.img" (again, no quotes). Connect your phone to your computer via USB and place the vrecovery.img file on the SD card. It should be at the base level of that card and not stuck inside of any folders. This will be replacing the file called vrecovery.img that you likely created the first time you went through the guide.
If you were able to do both of these things then you are ready to go back to step 4. from the rooting without a computer guide. Please understand what it means to have items like "flash_image" available on your sdcard as things like this are important.
If you have any questions about what any of the commands are doing in that guide, please ask before you proceed. Each of those steps has a distinct meaning and need to execute without generating an error. If you encounter any errors at all, then please STOP and post what the error is so that you can get help to resolve it.
EDIT: Actually you'd only have to repeat part of step 4. If you've been able to previously flash a recovery that means you've already successfully installed "flash_image" from your first trip through the guide. So you'd just need to do the following: (note - $ or # is the prompt you should see in terminal emulator and red underscores "
_" are just spaces)
$ su(return)
# flash_image
_recovery
_/sdcard/vrecovery.img(return)
# reboot
_recovery(return)
If that all works and you're able to get into recovery, then make a backup, and then exit out (reboot). Then read some more to make sure you are 100% comfortable before going in and flashing a new ROM.