The compressed filesystem is larger than the iso9660 specification allows for a single file. You must try to reduce the amount of data you are backing up and try again.
Today I did a complete fresh install, (thinking I had added a bunch of garbage or something that was taking up space), and only installed the few programs that I need right now. Tried Remastersys again and still got the same message!! What did I do wrong?? It was working before . Has anybody else had that problem?
Note: It appears the only file that is that large is a Remastersys file itself.