StarOffice and OpenOffice.org (Sun builds) for Windows contain a CLI-UNO bridge. This bridge requires a .Net Framwork. The minimum version of the framework depends on the compiler which was used to build the office. The official Sun builds for OOo 2.0 (the first version containing the bridge) until now (August 2007. latest version is 2.2.1) have been made using Microsoft Visual Studio 2003. This development environment requires a .NET Framework 1.1 and therefore this version is also required by the offices.
OpenOffice.org can also be build with VS 2005, which uses the .NET Framework 2. Then the office needs also version 2 of the framework.