Help please, on dvd recording

was wondering if anyone can help me out, ive recently bought new laptop and it has a different dvd recorder.

Its a Matshita DVD-RAM uj-815a

i tried to burn something using my blank dvds from my last computer with no joy, they were 4x dvd+r. do i need to use dvd-r with this recorder??? also what is the difference between + and - discs

According to this site you need - media.

That drive cannot burn to + media.