Dave, as someone that has customers that use Front Page as you are using it, I can feel for your ISP. Lately we seem to be having a rash of calls about the same problem. We have tried rebuilding their sites, re-installing the server extensions, re-creating the front page web and all the permissions and it is still unreliable on a larger busier site.
They have finally with some prodding decided to drop Front Page as their editing tool and move over to Dreamweaver. Do all of their work locally and then push it to the site via FTP. This is the way we do it for our sites as well as the majority of our clients that do their own web work. Front Page just seems to be too tempermental and inefficient once a site has a lot of pages.
I would think that you would always want to do the changes locally so that it could be checked prior to going live on the site. Plus you will end up with a complete up to date copy of the site locally should something happen to the server and your ISP not have proper or timely backups. If you have multiple people working with the site, Dreamweaver can work in colaboration mode where files must be checked out and back in when they are worked on. This seems to work quite well.
I know it is not a fix to your Front Page woes, but if you are serious and wish to grow you should probably be looking in this direction anyway.