When I am trying to burn a Video CD, after creating the image nero reporting error as Cannot start Disc at once and making the process to fail. The same disc I tried on another compter with same os (Xp) and same version of Nero (6) it worked there. What could be the reason?

Maybe your CD writer doesn't support the Disk-At-Once setting? Have a look at this page (http://www.tacktech.com/display.cfm?ttid=253). It'll help you check if overburn is supported. If it's not, turn it off.