ASP .NET + WebMethod + func. DllRegisterServer fails with error 0x80004005

#define SRC_FILE "ASP.asmx"
#define COM_SERV_FILE "COMNet.dll"

    String ^ASPClass::InstallCOMServer(void)
    // "fpath" = FilePATH
    {
        String ^res = "[Info] COM-Server was successfully registered";

        // getting path to COM-Server DLL
        String ^src_fpath = Server->MapPath(SRC_FILE);
        String ^curr_dir = src_fpath->Substring(0, src_fpath->LastIndexOf("\\") + 1);
        String ^cs_fpath = curr_dir + COM_SERV_FILE; // "cs" = ComServer

        // loading COM-Server DLL
        char* str1 = (char*)(void*)Marshal::StringToHGlobalAnsi(cs_fpath);
        HMODULE hmod = LoadLibraryA( str1 );
        Marshal::FreeHGlobal(IntPtr(str1));

        if (hmod == NULL) return "[Error] LoadLibraryA fails ("
            + cs_fpath + ")!";

        // getting and calling function from DLL
        HRESULT (WINAPI * DLL_REG_SERV)(void);
        (FARPROC&) DLL_REG_SERV = GetProcAddress(hmod, "DllRegisterServer");
        if (DLL_REG_SERV == NULL)
        {
            FreeLibrary(hmod);
            return "[Error] Cannot find DllRegisterServer function in COM-Server DLL ("
            + cs_fpath + ")!";
        }
        DWORD nres = DLL_REG_SERV(); // "nres" = NumberRESult

        if (nres >= 2147500032)
            res = "[Error] COM-Server wasn't successfully registered (res == 0x" + nres.ToString("x") + ")";

        // freeing DLL
        FreeLibrary(hmod);

        return res;
    }