[CMake] problems with FindBoost

[Dominik Szczerba]

FindBoost (cmake 2.8.4 here) fails to find DLL - but not static -
version of boost 1.46.1 on Windows 7 with Visual Studio 10 64 bit. The
boost_thread library is needed.
The filepath's I add in cmake-gui are always reset to NOTFOUND if and
only if DLL version is needed. Static is no problem.
Any pointers how to debug this are very welcome

Regards,
Dominik