Apple\'s iOS developer guidelines state:
3.3.2 — An Application may not itself install or launch other executable code by any means, including without lim
I think what Apple means is your application should not depend in another module, compiled product or executable in order to work that will be downloaded from a website/server and that compiled add-on was not reviewed by Apple.
Basically when I asked something similar they told me something like: "If your application will download another executable compiled code that such a ftp downloader, key decryption tool or something of this kind that was not approved my Apple. You are available to download data or files (such as XML, HTML, PDF files, images) that does not represents an application.