I encountered the same issue, I was attempting to add NHLamba
Extensions to my project. I ended up downloading the latest
NHibernate (2.1 beta), Re-rolling my FluentNHibernate dlls with it,
and then rolled all of the new dlls into my project (overwriting the
2.0.4.1GA that were in the project). This was all a S#arp generated
project started at the beginning of May. Once I did this, the
NHibernate.Validator dll started complaining about the incorrect
version of NHibernate. So I started searching for an update to the
Validator, which I could not find, and could not get source code.
I was about to throw my box out the window, when, on a whim, I decided
to update my original svn checkout of S#arp Architecture, and I got a
HUGE update. I looked at the release notes, and they had updated to
NHibernate 2.1, with a new release of Fluent and Validator.
Apparently, I was doing all of this at the exact same time as Billy
(and others) were working on the new RTM. So, I grabbed their new
NHibernateValidator, mixed with the NHLambaExtensions, and it worked
REALLY well.
SO, this all relates, in that the changing of so many interrelated
assemblies (at the core NHibernate.dll), unless you want to have to
code the version binding redirects, all of the dependencies have to be
fixed, or you will get these issues.