Web login forms provided in Lotus-created templates such as webmail redirect (iwaredir.ntf) and Quickr (and probably others) will not work if the server is set to disallow anonymous HTTP access (Server document: Ports --> Internet Ports --> Web --> Authentication options --> Anonymous --> No). When anonymous access is disabled, the images and imported scripts on the login form are not loaded, breaking the login page.
We as developers have a crude work-around which is to copy images and scripts to the icons folder (which is not secured) and reference them from there. The Lotus supplied templates do not do this (which makes sense being that it is not a great workaround).
Lotus should find a proper to handle this situation for template developers (and others) so that the server can be secured without breaking the login page. At the very least, fix the supplied login forms by moving the referenced resources to an unsecured folder.