Following changes after version 0.5.6 to BaseRollingFilestream the dateFile modeule cannot be found when attempting to configure a dateFile appender.
Changing 'util.inherits(BaseRollingFileStream, stream.Writ..'
What version of node are you using?
What version of node (not log4js) are you using? email@example.com will only work with node v0.10.x. This is specified in the package.json, so npm should stop you from using it with node less than 0.10. In issue #123 I tested firstname.lastname@example.org with node v0.10.1, with both a dateFile and a file appender and it worked fine.
You might want to specify the exact version of log4js in your package.json. 0.5.6 or 0.5.7 will work with node 0.8.x. That way you won't get any surprise upgrades :)