CFURLEnumeratorGetNextURL returns Error which has different URL and filepath error key

CFURLEnumeratorGetNextURL search for next file. If my folder name has "#" it is not searching file correctly. When I closely analysed using CFErrorCopyUserInfo function, I got a dictionary that has different NSURLErrorKey and NSFilePathErrorKey. What is the difference between both the error keys. The file is correctly present at NSURL' s value. How does it get the value of NSFilePathErrorKey.