|So, each one of your emails is in a folder "Project Name/Correspondence/Email/08-09-02_Email from blah to blah rec/sent etc"?|
Read the article linked below. There are many parameters involved in burning an optical disk.
Packet writing may solve the issue, not sure about that.
Do you have Roxio Drag to disk. Drag to disk is a packet writer. You could try it.