You can't just randomly pick and choose items to put into a VIDEO_TS folder, the .ifo files have specific information about all the files including menus and extras in them and if they are not there Nero will choke. Use something like Dvd Decrypter to extract the files from the dvd, it will make its own VIDEO_TS folder for the files and then use Dvd Shrink to eliminate files you don't want.
By the way, you cannot copy files from a dvd disk and paste them into a VIDEO_TS folder and expect ANY dvd burner to read them correctly if the info in the main ifo file does not match whats in the folder.
There is a way to burn anything you want to put in the folder but its complicated. Using Ifoedit and Vobedit you can do it and here are some links that can help you.
Ifo edit page with a list of tutorials:
A tutorial on How to author & burn a DVD from VOB trailers/files:
And the actual tutrial page:
I hope I was of some help even if it seems a little disheartening. IfoEdit is a cool little tool that can do ammazing things if you find the right instructions.