Not 100% sure but try creating the project using Visual Studio 2005 firts
then open it with Expression Blend.
Otherwise manually modify the project file and make it compatible with
VS2005.
--
Corrado Cavalli [Microsoft .NET MVP-MCP]
UGIdotNET -
http://www.ugidotnet.org
Weblog:
http://blogs.ugidotnet.org/corrado/