You always know if you have the latest HomeSeer xAP plugin running because at the top of the xAP related pages within HomeSeer it says "There is a new xAP Conduit available, please visit http://www.mi4.biz for more information" should it be out of date. Currently latest is v2.0.313
When you say a constant stream of messages what do you actually mean - how many messages per minute are you seeing (there is a figure supplied in the bottom of a xAP Viewer window and it is also shown in the Stats page of the HomeSeer plugin)
HomeSeer will send xAPBSC.event messages whenever a device setup to originate xAP commands changes state. It will send a xAPBSC.info message periodically for each such device (around every 10 minutes per device I believe). It will also send a .info message if you ask HomeSeer for the state of a device using a xAPBSC.query command or if you ask a device to change state to one that it is already in. If you are seeing a few messages per second then it is likley that you have created some form of loop eg toggling a device state that itself toggles its state. If you stop XLobby does that stop the messages , if so something is creating a loop between the two applications. Normally loops show as .event rarher than .info messages however.
Is it possible that some of the devices that you have enabled for 'xAP' r are changing state very frequently (eg being updated with a time figure or something). You can enable/disable xAP on a per device basis should you wish. There is also an issue with one of the plugins - a 'motion sensor' one from memory which constantly updates devices - are you using that by any chance ?
The other thing to look at is what originally created these devices in HomeSeer - were they created from a xAP message (device) or are they plugin/inbuilt devices within HomeSeer. You don't want devices that were created by xAP messages to themselves send xAP messages as again loops can be set up if you are not careful.
Lastly - I would try running a standalone xAP hub (or Viewer) rarher than the hub built into the XLobby plugin. That will at least eliminate a hub issue.
K