> When the executable terminated, I could see log lines where
> it failed to clean up properly.
>
> As far as I could tell, the cleanup is run as part of the
> Ruby process which the main application also runs in.

Almost... The cleanup is done by EEE, the bootstrapping program
which unpacks the files, invokes the application and cleans up.
If it can't delete a file or directory, it just goes on with
the next one. Such an orphaned file is not important for the
application itself, nor is it for EEE.

Anyway, the OS should cleanup its temp directories on a regular
basis...

(EEE is part of the run time part of RubyScript2Exe.)

gegroet,
Erik V. - http://www.erikveen.dds.nl/