Thread:Project:Support desk/Bot or so?/reply (3)

Hello! This error comes, because your hoster hosts php in safe_mode. In this mode, php's mail function will return false with a warning when called with the fifth parameter (MediaWiki uses this parameter iirc) which MediaWiki interprets as an error while sending the e-mail (and add the above error message), see the Manual for more information.

You should ask your hoster to disable the completly senseless safe_mode. This function is deprecated in php 5.3 and removed in 5.4 anyway.