I realize I named this post incorrectly. It's a buffer underrun error.

I purchased Popcorn 2 yesterday and so far I've been able to successfully burn 2 DVDs and make 11 coasters. I'm very frustrated and very disappointed. Partway through the writing process I get the "buffer underrun error" even when I have underrun prevention turned on and write speed set to the lowest possible option.

I'm using an iBook G4, Popcorn 2, a LaCie d2 DVD+-RW Firewire burner, and Sony DVD+R 16x speed compatible blank media. I'm creating a disc image first and then attempting to burn the disc image.

What can I do to fix this?

I have a very similar set up as you....
It works GREAT for me but I don't burn the disc image...
In fact I don't even create one....
I create a video & audio TS folder via mac the ripper and drag that into Popcorn.....
Try that!

I've tried that. I recieve the same error.

You are doing everything correctly so the only thing I can think of is a problem between the drive and the media. Check the LaCie support site to see if there is a firmware update available for your drive. Also, try a different brand of blank media (LaCie drives work well with Verbatim media) to see if that fixes the problem.

How much ram does your iBook have? Shutting down and starting up the iBook (not just restarting) may help, too.

Thank you for your suggestions. I tried updating firmware (I just purchased the drive, so I don't think it was even necessary), and I tried a Verbatim disc after shutting down and starting up my computer. This time I didn't receive any errors, it simply froze about halfway through writing.

My iBook has 768 MB of ram.

This may be a Firewire bus issue. Odd Firewire and USB problems sometimes are created during incremental system updates. The fix is to download and apply the latest combined system update on top of your existing system. Give that a try.

Also, find the Hardware Test disc that came with your iBook and run the extended test. This will show if there is anything amiss with the Ram.