Not sure here, but could this be determined by the "Cookie Expiration Time" designated in Control Panel » Primary Settings » General » Advanced Options?
What's yours set at? Mine's at like 30758400 secs (142 days)
...or is there a time out for the PHPSESSION? I don't know enough about it, just throwing these out there.
In any event, for posts THAT long, people might want to get into the habit of using Notepad or something.
