Importing C# dll in a VC++ 6.0 project

I have two projects. One C# project and one VC++ 6.0 project. I would like to import the C# project's functionalities in the unmanaged project. I followed this guide to create the dll and I imported in the VC++ 6.0 project using:
#import "..\ManagedDLL\bin\Debug\ManagedDLL.tlb" raw_interfaces_only

My project is built ok but when I try to run it I receive an exception from the debugger when I try to initialize the COM object using:
HRESULT hr = CoInitialize(NULL);

The messages I get in the Output are:

Loaded 'C:\XXXXX.dll' No native symbols in symbol file.
First-chance exception at 0x75befbae in W7.exe: Microsoft C++ exception: EEFileLoadException at memory location 0x0349bde0..
First-chance exception at 0x75befbae in W7.exe: Microsoft C++ exception: [rethrow] at memory location 0x00000000..
First-chance exception at 0x75befbae in W7.exe: Microsoft C++ exception: [rethrow] at memory location 0x00000000..
First-chance exception at 0x75befbae in W7.exe: 0xE0434F4D: 0xe0434f4d.
First-chance exception at 0x75befbae in W7.exe: Microsoft C++ exception: [rethrow] at memory location 0x00000000..
First-chance exception at 0x75befbae in W7.exe: Microsoft C++ exception: _com_error at memory location 0x0349ec60..
A first chance exception of type 'System.Runtime.InteropServices.SEHException' occurred in W7.exe 'W7.exe': Loaded 'C:\Windows\System32\version.dll', Cannot find or open the PDB file
An unhandled exception of type 'System.Runtime.InteropServices.SEHException' occurred in W7.exe

I dont know where to look...I would be grateful for any help.