Hello Svetlana,
It means :
"There is nothing to pardon"
or
" You flatter me".
Happyboy gave good examples above.
Notice that if 哪里 is in the sense of 'where' ,it will be just mentioned once or repeated as in 哪里 ?哪里 ? .
The other expression 哪里哪里 is not separated by any commas or interrogation marks to give the above mentioned meanings.