AppleScript works in Script Editor but not as application - applescript

Question

I am pretty new to programming, especially with AppleScript. I wrote a simple script for Valentine's Day to play a song from iTunes and then open a flash animation file in Safari. When I run the script in ScriptEditor, everything works as desired, but when I export as a standalone application, it fails at the command to enable full-screen mode. I am assuming it is an issue with System Events. To be clear, the application functions to the end, but at the keystroke command I hear an alert sound and the window remains as-is.
I am running Yosemite, and am fully updated.
Ideally, I would like to open the file in Google Chrome to utilize Presentation Mode, but I can't even get Chrome to open the file.
Thanks for any advice! Here is the code:
tell application "Finder"
set visible of every process whose visible is true and name is not "Finder" to false
close every window
end tell
set volume output volume 75
tell application "iTunes"
set currentVolume to sound volume
if player state is playing then
stop
back track
end if
play track "The Promise"
set player position to 6
end tell
delay 4
tell application "Safari"
activate
if (count of windows) is 0 then -- Remove "if" statement if you don't want to make a new window if there is none
make new window at front
end if
open (POSIX path of (path to home folder)) & "/Desktop/beMine/beMine.swf"
tell application "System Events"
tell process "Safari" to keystroke "f" using {command down, control down}
end tell
end tell

Answer 1

I agree with Jerry Stratton's comment that it could be an accessibility issue. However it also could be that you are issuing the keystroke command before Safari is ready to accept it. If it's opening a file then it could be busy and miss the keystroke command.
Also, I would move the system events code outside the Safari code and also just tell system events, rather than the Safari process, to perform the keystroke command. Try this as the Safari and System Events parts.
NOTE: I can't get Chrome to open a file either.
tell application "Safari"
activate
if (count of windows) is 0 then -- Remove "if" statement if you don't want to make a new window if there is none
make new window at front
end if
open (POSIX path of (path to home folder)) & "/Desktop/beMine/beMine.swf"
end tell
tell application "Safari" to activate
delay 1
tell application "System Events"
keystroke "f" using {command down, control down}
end tell

Answer 2

Most likely you’ll need to allow your standalone application to use System Events. At some point you needed to do that for Script Editor; you’ll need to do the same for your standalone app.
You’ll find the option in System Preferences under Security & Privacy, then Privacy, and then Accessibility. There’ll be a list of apps, and your app is probably listed there without a check for “Allow the apps below to control your computer.”
You may need to use the “+” button to add your app to the list.
I have verified that I can use this simple script to make Safari full-screen; it will work if the app is given permission under Accessibility, and it will silently fail if not.
tell application "Safari"
activate
end tell
tell application "System Events"
tell process "Safari" to keystroke "f" using {command down, control down}
end tell
This is Yosemite, Mac OS X 10.10; it may be different in other versions of Mac OS X.