I've recently taken over responsibility of a Cruise Control continuous integration server, although I know very little about either Cruise Control or Nant. But, such is life.
One of the regular build jobs this is supposed to do is to execute a Nant script that backs up files and data from one of live servers to a backup server. I've discovered that this has been failing pretty much as far back as user interface will let me see.
The error message is always the same:
Build Error: NAnt.Core.BuildException
Cannot copy '[filename].bak' to '[server]'.
But it doesn't always fail at exactly the same spot.
The Nant script that's executing is pretty much several iterations of this copy code:
<copy todir="${backup.root}\{dirname}">
<fileset basedir="s:">
<include name="**/*" />
</fileset>
</copy>
Although some of the commands are 'move' rather than 'copy'.
The fact this happens at different points in the scripts suggests to me that this is either down to a timeout, or to the script being unable to access files that in use by the system when the script is running. But I've never been able to get a successful execution through, no matter what time of day I set it to run.
The error messages are not particularly helpful in identifying what the problem actually is. And googling them is not particularly enlightening. I'm not expecting a solution to this (though one would be nice) - but it'd be enormously helpful if I could just get some pointers on where to look next in terms of identifying the problem.
As this is a backup you could set the copy task to proceed on failure until you identify the problem. Obviously you don't want to leave it that way permanently.
See http://nant.sourceforge.net/release/0.85/help/tasks/copy.html
I would add the verbose='true' and failonerror='false' attributes to the copy task and see if that helps.
Setting overwrite based on your scenario may also help.