VCD use 44.1 kHz audio sample rate and DVD standard is 48 kHz. So you probably need to convert the audio. However the video streeam of VCD can normally be used as a source for DVD authoring.
I remember that sometimes VCDEasy had problems to rip the VCD directly from disc.
Then it may work better if converting the disc to a image file first (do not remember what format was supported, .img or maybe .iso).
You can use tools like Clone CD. There are also a VCD-extraction function in isobuster.
Here are some guides:
http://forum.videohelp.com/topic141726.html
http://www.digitalfaq.com/guides/vid...rt-vcd-dvd.htm
http://www.mediachance.com/dvdlab/tutorial/svcd.html