Oops, there are two queries to grab a calendar item. One if the use ofattachments is disabled (which I'd changed earlier), and one if attachmentsare enabled (which I'd missed earlier). Thanks to Michael at MGH for catchingthis while testing.
White space in URLs tends to break them ... and if you do so in an IMGtag, you get the little blue-box "?" or red "X" depending on the browseryou use ...