VCDEasy Giving buffer under run error

Im trying to burn mpeg-1 files to CD using VCDEasy. I got a buffer under run error and I heard the siren sound. What is a buffer under run error and is it somehow related to the write speed which was automatically selected as 4x? Should I lower the write speed to avoid the buffer under run error?

This is when the buffer runs out and there’s not enough data to send to the burner. Commonly reported factors that make this more likely to occur are:

[ul]
[li] Trying to do other things with the computer when you’re burning[/li][li] you have most of your memory used up[/li][li] your HDD is fragmented.[/li][/ul]

I wasnt doing anything else on the computer and I had just defragmented my HD. So I tried to lower the writng speed and it worked. But I guess buffer under run is mostly an issue with verburning cause I was trying to burn 850MB onto a 700MB cd