sony movie studio please help with vob files

I have extracted vob files of of an existing dvdr. I am editing the vob files for content. When i combine any of the existing vob files, I cant get an uninterupted stream. The software always creates a slight gap inbetween the files. So the result is that i have gaps inbetween my video files. I want to combine the existing vob files with out any gap or clicking. There are no gaps or clicking on the source disk