Using a C++-DLL in a Webservice

Question

Hello,

I have written a Webservice in .Net 3.5 with C#. Inside I use a C++-Dll (CLR-DLL). In Visual Studio on the ASP.NET Development Server everything works fine, but on IIS it always shows a BadImageFormatException: "The Assembly ... or one of its dependencies was not found. You tried to load a file with a wrong format". I hope somebody can help me, it is really important for me. Thank you.