Failed to create the same file after delete it when upload file in Chrome

Currently, I have implemented the file uploading in my tiny web server with C++.

Here are the logic of my apps:

• Parsing the HTTP message, get the upload file name and content.
• Remove the old files with same file extension (business logic)
• Save the new file with uploading content into my apps folder

Code sample:

void remove_file(char* pfileextension) {
    CFileFind finder;
    CString SearchPath = MyApp::GetDirectory(DIR_ROOT) + _T("*.*"); 
    BOOL bFind = finder.FindFile(SearchPath);   //Search current work directory 

    while(bFind) {
        bFind = finder.FindNextFile();
        if(!finder.IsDirectory() && 
            !finder.IsDots() && 
            (!strcasecmp(finder.GetFileName().Right(4), pfileextension))) {
            DeleteFile(finder.GetFilePath());
        }
    }
    finder.Close();
}

bool save_upload_file(char* body, int len, char* filename, char* path){
    char* pextension = strrchr(filename, '.');
    char* paction = strrchr(path, '/');

    // Filter out the license file and control file
    if (!strcmp(paction, "/licensefile")){ 
        if(!pextension || (pextension[0] == '\0') || strcasecmp(pextension, ".lic")){
            send_error(200);
            return false;
        } else {
            remove_file(".lic");
        }
    }

    try{    
        CString szFilename = MyApp::GetDirectory(DIR_ROOT);
        szFilename += CString(std::string(filename).c_str());

        std::ofstream ofs (szFilename, std::ofstream::out | std::ofstream::trunc | std::ofstream::binary);
        if (ofs.fail()){
            int err = GetLastError();
            return false;       
        }

Now I test it with the case: upload the file under the my apps. It works well under IE, but fails under Chrome.

After debugging it under Chrome, I find the ofs.fail() return true and the error code is 5, which means Access Denied. Further investigation, the file is still in my app folder after remove_file() invoked, I think it may cause the ofs.fail(). By Contrast, this file is removed under IE after remove_file(). Why??

Searching some knowledge, I guess it may be caused by sandbox of render process in Chrome. I am confused...