Mixed managed\unmanaged dll causing problems with std::vector clear()

[hanthehead]

In order to use a C# dll from our unmanaged C++ project I have created a mixed managed\unmanaged c++ dll.
This dll is passed an unmanaged class which contains vector<CDBRecord> m_vecRecords member variable. Within the managed C++ dll m_vecRecords is added to. This all works fine until our unmanaged C++ project attempts to m_vecRecords.clear() and I get an exception.

"Microsoft C++ exception: std::bad_alloc at memory location 0x0012ed68.."
and execution stops at
> msvcp90d.dll!std::allocator<char>::allocate(unsign ed int _Count=2315203557) Line 151 + 0xb bytes C++

    void destroy(pointer _Ptr)
        {    // destroy object at _Ptr
        _Destroy(_Ptr);
        }

then

    pointer allocate(size_type _Count)
        {    // allocate array of _Count elements
        return (_Allocate(_Count, (pointer)0));
        }
 

Here are some exerts of my code....I hope you can help!

// IReadDatabase.h
#pragma once
#include "stdafx.h"
#include <vector>
 
#pragma unmanaged
 
class StringPair
{
public:
    char *key;    /* optional element of type xsd:string */
    char *value;    /* optional element of type xsd:string */
    StringPair();    /* transient */
};
 
class CDBRecord
{
public:
    CDBRecord(long dbID = -1);
 
    StringPair *__ptr;
    int __size;
};
 
class CHitlist
{
public:        
    CHitlist() {}
 
    long                m_hit_total;
 
    std::vector<CDBRecord>   m_vecRecords;    
};
.....
 
// ManagedDll.h
 
#pragma once
 
#include <IReadDatabase.h>
 
#using <..\..\Shared Libraries\c#DLL.dll>
using namespace System;
using namespace System::Collections::Generic;
using namespace c#DLL;
 
#pragma managed
 
namespace ManagedDll
{        
    bool CManagedDll::AddRecord(CHitlist* pHitlist)
    {
        CDBRecord rec;
        bool bRet = GetRecord(&rec);
 
        if (bRet)
            pHitlist->m_vecRecords.push_back(rec);
 
        return bRet;
    }

....