Please be more specific in: -What Kind of DVD+RW you are using -Operative System -Burner Brand -Program to Burn DVD -Kind of error that is appearing With that info we can be more helpfull in finding the source of your problem, also you can do a brief google search if you find any speficic error code, generally someone had that problem before and maybe its problem was already answered on the web.
paztelu is right. please be more specific with the problem so we can narrow down our suggestion on what we can do to your problem. is this the first time you can't record? do you recently record a movie in the dvdrw before the problem happens? have you tried other blank media besides the one you are using?