I wish I could help, but I just tested mobilePickMedia in an Android app and discovered a bug:http://quality.livecode.com/show_bug.cgi?id=19279
To try to get more attention here you may want to consider changing the title of this thread to something like "problem with mobilePickMedia" so folks can better anticipate what the thread is about.
You may also want to consider asking your question on the use-livecode discussion list. There's some overlap between the two audiences, but also many only here in the forums or only there on the list. Might be good to see if you get any interest there.
For some reason I've been having alot of bad luck with Livecode this year.
IIRC it hasn't been just LiveCode, but mostly that you've been doing a lot of mobile development. Dealing with more restricted OSes, single window GUI, limited file system access, and other constraints we don't have on the desktop make mobile development like building a ship in a bottle.