I always used to have problems when recording music CD's with "buffer underrun" error message.
I have just read that I should change my computer from desktop PC to Network Server because it will increase the size of the file system cache memory, which can help to prevent buffer underruns when recording in Disc At Once mode. It says to make the change. right click on My Computer, select Properties, System Properties, Performance Tab, File System and make the change on the "Typical Role" drop down menu.