I can't comment on the Mac mobiperl install because I don't have a Mac.
When trying to change the book title are you using the following command structure (which is a bit longer for Amazon .azw books)?
mobi2mobi originalFILEname.azw --outfile revisedFILEename.azw --exthtype updatedtitle --exthdata revisedBOOKname
Edit: Oops, you said "author" not "title". Ignore the above for now (you'll need it later).
Last edited by daffy4u; 11-16-2008 at 11:15 AM.