running Crystal Report from a dll

We have a Visual Studio C# project that contains some Crystal Reports, and is compiled as a DLL.  I want to run those reports for debugging purposes.

I've set up another project that references the DLL, and created an *.aspx page to call the report but I keep getting parser error messages, because it won't recognise the CodeFile/CodeBehind from another project. I'm not getting anywhere on google, can someone point me in the right direction?  Does anyone know of a tutorial somewhere that explains how this is done, step by step?

Thanks.