my dvd recorder acting weird

I've been trying to tape stuff from vhs to blank dvd's the past couple of nights. And the blank dvd that I had doctor who and heroes on suddenly wouldn't record! I didn't know what button I pressed but when I hit the open button and close button it read unsupportive disc?!  When I put in another one that I had recorded stuff off tv  I went to turn it off and it said the disc was not supportive, please put in a dvd+r or -r in.  So I took that one out tried several others that I recorded and it came up with please put in another disc, not sufficient space. Which was the normal message. So I finally decided to put in a blank disc instead of risking wiping out another disc in its place. I think that was the wise thing to do. But the thing is I have to rerecord all the other stuff that I did the past couple of days. Which is a pain! I was kind of ticked off about that.