help me! can u help me explain mean of this sentence?

Experimental results
and the proposed theorem show that the hidden message is error-free against the JPEG
distortion under the quality setting as low as 25.

I'm a studen IT,now i translate document English but i don't know what is mean of "error-free against".

help me!

thank you! everybody! 

OH! nobody help me!

hmm that is strange English.

is this related to steganography?

could you please explain the context a little more? 

So, I hope you probably know, what "JPEG distortion" is?  "Against" is just a preposition. "Error-free" means "without errors or mistakes". The whole phrase is suppose to mean that hidden message is not affected by distortion if the quality setting is lower than 25.
BTW, what are you studying?

aljensen, I have found the related text on the internet: 

http://debut.cis.nctu.edu.tw/Publications/pdfs/J42.pdf

http://citeseer.ist.psu.edu/598368.html

Abstract: this paper, we propose a new image embedding technique for solving the prisoners' problem. The proposed method embeds the messages to be conveyed by modifying the mean intensity value of image blocks, and the resulted stego-image can be stored in the JPEG format with a low quality setting. Experimental results and the present theorem show that the hidden message is error-free against the JPEG distortion under the quality setting as lowas25. Furthermore, the existence of hidden message is not..

error-free as a person has already explained means without error or mistake

the hidden message is error-free against the JPEG
distortion under the quality setting as low as 25 could also possibly mean the hidden message is free of any JPEG distortion even at a quality setting as low as 25

http://www.actionscript.org/forums/showthread.php3?t=16017

Haha, I am a person

Thank aljensen, Pavlionka, hanimostafa, tiffintime

i 'm training about Steganography in image JPEG, and Watermark in Video.

if you training too. can you help me about problem follow:

1. I can't read DCT coefficient, and Huffman in Header of JPEG use vb.net or C#.

2. You can show for me many algorithm watermark use video or image.

3. can u for me you email, i can contact with u examine this problem.