PHP warnings when clicking "view invitations" link

You receive the following errors when clicking the "view invitations" link on any event-enabled node:

    * warning: Invalid argument supplied for foreach() in /modules/node.module on line 359.
    * warning: implode() [function.implode]: Bad arguments. in /modules/node.module on line 363.
    * user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1 query: SELECT DISTINCT(n.nid), n.vid, n.type, n.status, n.created, n.changed, n.comment, n.promote, n.moderate, n.sticky, r.timestamp AS revision_timestamp, r.title, r.body, r.teaser, r.log, r.format, u.uid, u.name, u.picture, u.data FROM node n INNER JOIN users u ON u.uid = n.uid INNER JOIN node_revisions r ON r.vid = n.vid WHERE in /includes/database.mysql.inc on line 120.

The problem is this path points to rsvp/invites/node/$node->nid where the calling function (rsvp_view_invites) is expecting a node ID as its first parameter. Trying to node_load a node object never ends well. ;)