StackOverflow Exception when usign external dll in ASP.net MVC

I am using a c++ ALPR library.

This is how I use the functions of this dll:

[System.Runtime.InteropServices.DllImport(DLL_NAME)]
public static extern short anpr_create(...);

This function works without problems in console application and Windows form programs, but when I call it in ASP.Net, I get the following exception:

How can I solve this problem?

Update:

Exception details

System.StackOverflowException
  HResult=0x800703E9
  Source=<Cannot evaluate the exception source>
  StackTrace:
<Cannot evaluate the exception stack trace>