MSBuild正确构建具有项目引用的项目，但不是来自解决方案

When i build a A.sln which includes 2 projects B.csproj and C.csproj which has internal project references it throws reference errors in MSBuild. But when i build B.csproj and C.csproj seperately in MSBuild it don't throw errors. And also building A.sln in VS IDE also don't throw errors.I'm using .NET 2.0 framework. Please find below the scripts used to build the sln and projs.When i build a A.sln which includes 2 projects