DLL Load Library - Error Code 126

Question

I'm using the 'LoadLibrary' from the Windows API, when I run the application, it throws me an error code 126. I read that it may be caused by dependencies, I checked what's wrong with some applications like Dependency Walker, but everything was fine.

LoadLibrary in the application:

            HMODULE dll_mod = LoadLibrary(L"path_to_dll");
            if(dll_mod==NULL){
                std::stringstream error;
                error << "Could not load plugin located at:\n" << file_full.toStdString() << "\n" << "Error Code: " << GetLastError();
                FreeLibrary(dll_mod);
                return error.str();
            }

Plugin code:

#include "stdafx.h"
#define DLL_EXPORT
#define PLUGIN_STREAM __declspec(dllexport)
#include <iostream>
#include <vector>
using std::vector;
using std::string;
// Init event (After the loading)
extern "C"{
PLUGIN_STREAM int onInit(char* argv){
return 0;
}
PLUGIN_STREAM void pluginInfo(vector<string> & info){
info.push_back("media_event=false");
    info.push_back("status_event=false");
    info.push_back("send_event=true");
    info.push_back("plugin_name='RadioStream'");
    info.push_back("description='This plugin was designed for that people that wants to listen to radio music.\nYou can register your radio and play it later, also we have a gallery of radios that you can check.\nThis plugin is original of Volt and it's originally implemented in the application.'");
    info.push_back("success:0");
    info.push_back("error:1=Could not open data file");
    info.push_back("error:2=Could not prepare plugin");
    info.push_back("alert:40=Could not connect to that radio");
}
}

Answer 1

Windows dll error 126 can have many root causes. The most useful methods I have found to debug this are:

1. Use dependency walker to look for any obvious problems (which you have already done)
2. Use the sysinternals utility Process Monitor http://technet.microsoft.com/en-us/sysinternals/bb896645 from Microsoft to trace all file access while your dll is trying to load. With this utility, you will see everything that that dll is trying to pull in and usually the problem can be determined from there.