USB cd/dvd burner question

I currently have a cd/dvd burner. External. In a USB box. And a while ago I used it with my 333mhz imac to burn a few cds with toast. It worked fine. I tried it today, and the computer recognised the burner fine. But I put a blank cd in it and it whizes for a few seconds. Spins up then spins down and then nothing. No app can recognise it when a blank cd is in it.

But it will read a few store bought music albums though.

Does anyone know what's up with the burner. As I'm really stumped as to what's going on here.

Thanks.

Have you try another brand of media?

Yes I have 4 different brands of cds here and all have the same problem. Yeah it's really strange. I tried like 20 different discs but to no avail.