[Android Apps and Games] dbrits:
Ok, to answer your question, yes, I am running it from the Terminal. Here's what is returned when I add your snippet of code:

Last login: Tue Sep 13 01:03:52 on ttys001
my-computer:~ my_computer$ export PATH=.:$PATH /Users/my_computer/Downloads/SpotifyController/install_osx
-bash: export: `/Users/my_computer/Downloads/SpotifyController/install_osx': not a valid identifier

The only way I could get it to work was to open install_osx in TextEdit and specify the exact location of spotify_install_osx.sh and the other items that are located in the resources. That seems to let me install it, but here's the result:

Last login: Tue Sep 13 00:57:00 on ttys001
my-computer:~ my_computer$ /Applications/SpotifyController/install_osx ; exit;

Installing Spotify Controller Server...

This installation file has been created for OS X. If you are not using that distribution, installation might not work, but it should be pretty straightforward to modify the script to work for your distribution.
This program requires Spotify and Java. This program will now check if Spotify is installed. Press enter to continue...

Please install Spotify

Spotify installed.
Proceeding with installation. Creating application shortcut...
Remapping commands to make OSX commands default

Program is now installed. We will now perform some tests to make sure your installation works correctly. First of all, please start Spotify manually and start playing a song.
Press "Enter" when you have started a song on Spotify:

Trying to pause the song...
2011-09-13 01:01:13.243 osascript[40158:903] Error loading /Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types: dlopen(/Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types, 262): no suitable image found. Did find:
/Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types: no matching architecture in universal wrapper
osascript: OpenScripting.framework - scripting addition "/Library/ScriptingAdditions/Adobe Unit Types.osax" declares no loadable handlers.
Did the music stop (press 'y' if it did)?
y
Trying to play the song...
2011-09-13 01:01:17.285 osascript[40168:903] Error loading /Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types: dlopen(/Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types, 262): no suitable image found. Did find:
/Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types: no matching architecture in universal wrapper
osascript: OpenScripting.framework - scripting addition "/Library/ScriptingAdditions/Adobe Unit Types.osax" declares no loadable handlers.
Did the music start (press 'y' if it did)?
y
Trying to skip the song...
2011-09-13 01:01:28.859 osascript[40184:903] Error loading /Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types: dlopen(/Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types, 262): no suitable image found. Did find:
/Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types: no matching architecture in universal wrapper
osascript: OpenScripting.framework - scripting addition "/Library/ScriptingAdditions/Adobe Unit Types.osax" declares no loadable handlers.
Did Spotify move to the next song (press 'y' if it did)?
y
Program is now installed. Simply run "Spotify Controller" from your desktop, or type "SpotifyController" to start the server. Make sure you have Spotify up and running with songs in the play queue.

To automatically start Spotify Controller Server when computer boots, add the application to System -> Preferences -> Startup Applications.

Don't forget to install the Spotify Controller app from Android Market.

If you experience any problems, see the file "TROUBLESHOOTING".

Happy Listening!
logout

[Process completed]

After what appears to be a successful install, I get the following when I launch SpotifyController.desktop.

Last login: Tue Sep 13 01:05:41 on ttys000
/Users/my_computer/Desktop/SpotifyController.desktop ; exit;
my-computer:~ my_computer$ /Users/my_computer/Desktop/SpotifyController.desktop ; exit;
env: xdg-open: No such file or directory
logout

[Process completed]

I'm sure what tinkering I've done has rendered the install useless. Any help is appreciated. I'd love to get this up and running as I paid for Macify but it hardly has any functionality. Thanks! :-)