Dll problem when it contain another dll function

Question

I package many c functions into a dll, it contain a few existed functions like cblas_sgemm (intel MKL). The whole program collapsed and exited and got a return value : 2 (0x2). But there is no problem when change the cblas_sgemm to a function written by meself. So I just want to know can I call a dll which contains another dll function in C#.

Thanks~