Used TMPGENC plus to concatenate mpeg files

why do I hear a short bleep between files? Has this ever happened to you? Can this be avoided?
A few more questions: how do I re-encode mpeg files that are not compatible in order to concatenate them and burn them onto a VCD? I wonder if there is a way to avoid the “compatibility control” and join the files together even though they are not compatible.
And, finally, an easy one I think: can I burn a DVD as a VCD??
Thanks for your help!

Haha, never ever.