Microsoft is known for introducing incompatibilities, whenever they release any updates or new version of their software. Latest in town is Microsoft Exchange 2007, which has changed a lot from its predecessor - MS Exchange 2003. MS Exchange 2007 has replaced the FE and BE server roles with something called CAS and Mailbox roles. CAS is more than its 2000/2003 counterpart, FE, where it handles both the business logic and renders OWA UI. With this change, MS Exchange 2007 introduced a new default OWA interface called "OWA" - that defines some new interface other than webDAV interface. This has currently broken Evolution Exchange connector from operating with MS Exchange 2007 servers.
Interesting and challenging days ahead!