I have clean installation (not an upgrade) of Spark 2.5.6 which is on a clean build of Windows XP Media Center Edition 2005 with all patches installed. When Spark loads on Windows startup, most of the time it doesn't load my MSN contact list, despite the MSN button on the toolbar lighting up indicating a connection. If I quit the application and reload it manually, the contact list usually loads fine. If for whatever reason the application is unable to obtain your contact list, why doesn't it continue to retry until it gets the list?
Spark is connecting to an Openfire 3.3.2 server running the 1.1.1 version of the IM Gateway plugin. Contacts from the actual Openfire server load just fine on all instances.