原文地址：http://blog.csdn.net/janssenkm/archive/2009/11/23/4859652.aspx
VS2008 在64位的系统(XP/Vista/Win7均是)中编译ArcEngine(9.3SP1)并运行时提示：没有注册类 (异常来自 HRESULT:0x80040154 (REGDB_E_CLASSNOTREG))
原因：ArcEngine9.3没有原生支持64位，而是以32位兼容方式运行
解决办法：在项目属性里设置“生成”=>“目标平台”为x86而不是默认的ANY CPU.
ESRI官方也是这么解决的：
http://support.esri.com/index.cfm?fa=knowledgebase.techarticles.articleShow&d=33000
Bug: Error: Class not registered(Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)
Article ID:
33000
Bug Id:
NIM007516
Software:
ArcGIS Engine Runtime 9.2, 9.3
Platforms:
Windows 2000, XP，win7
Description
Running an application from Visual Studio 2005 on 64-bit computers, displays the following error message:
"Error : Class not registered(Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)"
"Error : Class not registered(Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)"
Cause
When running a Visual Studio application, the default Common Language Runtime (CLR) platform in the Visual Studio is set to Any CPU. This default must be changed on 64-bit computers to compile the assemblies with the 32-bit, x86 compatible CLR.
Workaround
Change the default Platform Target CPU to allow applications to run on 64-bit machines:
- Right-click on the solution in the Visual Studio Solution Explorer and open the Properties window.
- Click the compile tab: Visual Basic, or the build tab: Visual C#.
- For Visual Basic, click the Advanced tab.
- Select x86 as the Target CPU (Visual Basic) or Platform Target (Visual C#).
- Rebuild the solution.