Welcome to android forums!
Here's the link to the lg esteem all things root page:
Esteem - All Things Root - Android Forums
Now, I don't know too much about LG devices, but do you have ADB installed on your computer? If so, you can plug in the phone and issue a command like this
that'll tell you if your phone is connecting...
If that works, then I'd *guess* that the computer isn't the issue.
I was just thinking, is it possible that one of the files is bad. have you done a md5 of them to verify that the files are all good? If you need a md5 program, I use md5deep on windows.
Hope that helps.