Error creating project :The imported project “C:\Program Files (x86)\MSBuild\Microsoft\Silverlight\v4.0\Microsoft.Silverlight.CSharp.targets” was not found
解决方法：
1、安装 Microsoft Silverlight 4 SDK http://www.microsoft.com/zh-CN/download/details.aspx?
id=7335
2、请确认你打开的项目是否是Microsoft Silverlight 4 的项目，SharpDevelop 眼下（4.4）不支持Silverlight 5
原文：http://www.cnblogs.com/lcchuguo/p/5215960.html