UNC problem

Why does this code not work on an UNC directory?. I have a similar FileExist function that works with the same FindFirstFile API call.

Code:

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BOOL WINAPI vbDirExist(LPCTSTR lpszDirName)
/*
        Last modified: 19/6/2001.

        Check if a directory exist.
        Returns true if the directory exist, otherwise false.
        To get extended error information, call GetLastError.
        TODO: Doesn't work on network
       
        Parameters ************************************************************
                lpszDirName:                Full directory name
        ***********************************************************************
*/
{
        char szBuffer[MAX_PATH];
        WIN32_FIND_DATA tWFD;
        HANDLE hFile = 0;
        DWORD dwError = 0;
        int len = 0;

        // Copy filename to buffer & remove trailing slash
        memset(szBuffer, NULL, MAX_PATH);
        lstrcpy( (LPTSTR)szBuffer, lpszDirName);
        len = lstrlen( (LPTSTR)szBuffer);
        if (szBuffer[len - 1] == '\\')
                szBuffer[len - 1] = '\0';

        hFile = FindFirstFile((LPTSTR)szBuffer, &tWFD);

        //if a valid file handle was returned, and the
        //directory attribute is set the folder exists
        if (hFile != INVALID_HANDLE_VALUE)
        {
                FindClose(hFile);
                return ((tWFD.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == FILE_ATTRIBUTE_DIRECTORY);
        }
        else {
                dwError = GetLastError();
                if (dwError == ERROR_FILE_NOT_FOUND)
                        // Clear error
                        SetLastError(ERROR_SUCCESS);
                return FALSE;
        }
}

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