Can not load .dll files of Nero SDK API!

Hi All,
I am currently using Nero SDK API to burn CD from my application, but I met a problem that I couldn’t debug because it was crashed when call NeroAPIGlueConnect(NULL) function of Nero SDK. While debuging I found that all .dll files of Nero SDK was not loaded.
Do you know this error? Please help me.Thanks.

NeroAPIGlueConnect dynamically loads the NeroAPI DLL. So if it crashes, your observation that no Nero DLLs are loaded is likely.

Do you link with the correct NeroAPIGlue.lib / NeroAPIGlueRT.lib?

Is Nero runing fine?

Does the NeroFiddles or NeroCmd examples work?

My nero works properly. With my application,it worked fine few days ago, and it was fine with some machines and crashed with some machines. And more I was using C#/C++.Net to develop my app.
I have tested carefully and it is fine with VC6.0 code(NeroFiddles or NeroCmd)