Is sendmail installed?

Unlikely on Windows.

Maybe use smtp?

Yepp, that's the way MIME::Lite works on Windows. Recent versions should auto-detect a missing sendmail executable, IIRC.

See the docs.

Adding MIME::Lite->send("smtp", $mailserver); or MIME::Lite->send("smtp", $mailserver, AuthUser => $username, AuthPass => $password); before creating or using any MIME::Lite object should do the trick.

Alexander