DVD writing problem with MATSHITA UJ-810

Hi everyone, im trying to write on a DVD but I don't really know what the problem is, when I insert a blank DVD appears this message, "insert a valid disk", I have no problem with reading CD's and DVD's, and with CDs writing not problem at all but is not the same with DVD writing.
I've a VAIO Notebook (PCG-FR872) ad the DVD/CD-ROM unit is a matshita uj-810, since I get it I had the idea that am able tu burn dvd's too but never try it before, now that i need to back up my files i found this problem.

i already use the notebook default software and other ones like nero (where the burn icon appears off)

Any help will be useful for me
thx

What blank media are you trying? It looks like only -R format is compatible with your burner and not +R. Could this be your problem?

I'm using TDK blank media, indeed it says DVD +R DVD Recordable. Whats the difference between a +R and -R.
The tap of my unit only has a 'DVD R/RW' so I dont know which one supports

The difference lies in manufacturing standards. -R was first out of the starting gate and overall is slightly more "universally" compatible. This is particularly true of older units. Nowadays, almost any burner will handle both +R and -R and with bitsetting of +R media, the compatibility issue with players is just about moot. As far as formats, click on this link and it will give you basic info. If you'd like more, there is a ton of info here on cd freaks, just do a search.

Your burner is a panasonic. A useful site for now and future use is Video Help.com. For your specific drive click on this link and scroll down. As you see, +R is not supported by matshita UJ-810 (panasonic UJ-810).

Pick up some quality -R media and you should be ok...Taiyo Yuden would be a good choice...easily accessible online.