"Undefined Control Sequence"

[Fede W]

Hello Forum!

I am completely new here. Please help !

I just chose "jox" reference style (full reference in footnotes, oxford style) and I get this message

"Undefined Control Sequence"

and Description:

I was expecting a `,' or a `}'---line 7599 of file 0C__Users_Federico_Dropbox_BibTeX_library.bib

Is my database (.bib) corrupted or badly built by Mendeley?  

Thanks thanks please help, thanks!