Dave Gower wrote:

I keep getting the following pairs of BOINC messages:

result...exited with zero status but no finished file.

and

if this happens frequently you may need to reset the project

Well since it has happened repeatedly I guess I need to "reset" the project. But how does one "reset"? Once again, with no help or FAQ, and no reset showing up on any menus I can see, I am stuck in really unfriendly territory.

Open BOINC and click your projects tab.  Right click on the project and you will see the option there.