Are you using xml to publish this data to the web? Just guessing that this might be why you see [fmxml] in the log.
BTW, these show up on a very regular basis, but not a regular schedule. Sometimes it is 4 minutes, sometimes 54.
Mac OS X 10.6.8.
We also are running SeedCode's Zulu calendaring plugin, plus we use some IWP for certain users. Not sure what form Zulu is using to transfer data. But we aren't intentionally publishing data using XML, that I am aware of.