it took me a while to understand the issue in this bug. all the events from worker are piped to the page mod by [the call to pipe() two lines down](https://github.com/mozilla/addon-sdk/pull/1449/files#diff-401a3bfd1210c470fb30bec33f56ea82L206) but that doesn't catch errors that happen at the time of worker creation. if you can explain this in a two-line comment a bit better, that would be great! :)