Newbie Q - autogen.sh. Can't execute.

Hello,

I'm new here, and new to LibreOffice development. I've been working my way through the steps to 
build LO by following the description on the wiki 
(http://wiki.documentfoundation.org/Development/Native_Build).
I have git cloned the source code to my local Ubuntu 12.04 machine, and am working with the master 
branch by default (i.e. I did not change my working copy/checkout a release branch).

I've hit a wall when trying to execute autogen.sh:

jim@JimdJ-Linux:/media/DEV/libo$ ls -l autogen.sh
-rw------- 1 jim jim 5556 Jul 24 16:54 autogen.sh
jim@JimdJ-Linux:/media/DEV/libo$ chmod 777 autogen.sh
jim@JimdJ-Linux:/media/DEV/libo$ ls -l autogen.sh
-rw------- 1 jim jim 5556 Jul 24 16:54 autogen.sh
jim@JimdJ-Linux:/media/DEV/libo$ sudo chmod 777 autogen.sh
jim@JimdJ-Linux:/media/DEV/libo$ ls -l autogen.sh
-rw------- 1 jim jim 5556 Jul 24 16:54 autogen.sh
jim@JimdJ-Linux:/media/DEV/libo$ ./autogen.sh
bash: ./autogen.sh: Permission denied
jim@JimdJ-Linux:/media/DEV/libo$ ./autogen.sh --help
bash: ./autogen.sh: Permission denied
jim@JimdJ-Linux:/media/DEV/libo$ sudo ./autogen.sh
sudo: ./autogen.sh: command not found
jim@JimdJ-Linux:/media/DEV/libo$ sudo autogen.sh
sudo: autogen.sh: command not found

(Forgive the 777 for now, please.) Did I miss something? Is it possible I need to explicitly 
checkout the master branch after cloning?

Jim