App Folder Level Scripts and using 'this.' statements

I am running into two problems with a folder level script.
 
Problem #1
I have a folder level script in the app folder and it calls a series of functions. In one of my functions I have a "this.getField" command in a catch statement of a try/catch sequence. Acrobat keeps telling me that "this.getField" is not a function?
I have the same thing in other parts of the function and it works fine.
 
#2
Similarly I have a "this.info" call in another function - it only reads info from the document property - it is not writing to it. There I am being told that "this.info" has no properties - when I know for certain that it does.
 
Are there any things I need to know about using the 'this' statement in an app folder level script?
 
can variables, declared in a function not be used in a catch statement?
 
one important note is that the scripts are being executed from a menu command only when a document is loaded into acrobat. The users of this script all have acrobat 7 pro.