Ruby无法加载DLL

I'm using Ruby 1.8.6 on Windows. I'm extending Ruby with C, that is I want to load a DLL into Ruby. But Ruby fails load my Dll. I use Visual Studio.net command prompt and integrate my DLL, namely prov.dll, into a C program, pro1.c. After that, I call those C functions through Ruby.I'm using Ruby 1.8.6 on Windows. I'm extending