Hi Danielle,
looking your example and infocenter example i find diferences:
AdminApp.install(application.ear '[other options -MapModulesToServers [['.*', '.*', 'WebSphere:cell=mycell,cluster=mycluster']]
AdminApp.install('DefaultApplication.ear', ['-appname', 'TEST', '-MapModulesToServers', [['.*','.*', 'WebSphere:cell=myCell,node=myNode,server=myServer']]])
take in mind ' ' and how many parameters and [] do you have open and close
only one question how are you developing the scripts?
I use normally Application Asembly Tool (AST) from WAS v7 the name i think that is Rational.... this tool is very useful to develop scripts and to test it. From my point of view is very usefull to check the wsadmin objets and functions and to know the correct sintax. comes with WAS.
of course you can do them with notepad