DMR-ES20D - Timer Recording Problem

I’ve just got the above recorder and it appears to work perfectly fine for everything, except one little thing.

I am currently using 8X single layer DVD-Rs (negative) discs to record programs off freeview. I can just press REC and, behold, it records! However, when I set it to use the timer it doesn’t want to work. Of course, I’m pressing the timer button to put it into timed record standy, but it’s when the program starts when the problem occurrs.

It tunes into the recording channel, reads the DVD for about a minute, then resets itself and reads SELF CHECK on the box for ages, then boots up again and tells me there’s been an error. When I press OK or RETURN, it reboots again and then tells me to check the disc. I press OK and then it proceeds with sticking to it’s pre-set timer, showing the program I want to record and then switch itself off. During that time it’s totally unresponsive.

Anyway, I know my discs are ok. I’ve tried on one I’ve already recorded something onto, and also with a completely fresh disc. I know this is a feature that I’m gonna want to use alot so can anyone help me at all?