Applescript won't run as .app but runs fine in AppleScript Editor

Question

I'm an experienced web developer.. but total applescript noob. so forgive me if this is a silly question.
I'm calling my script it from Flash via fscommand to launch a PDF using finder, rather than a browser.
The script works great from AppleScript Editor when i hit run but when saved as a .app it doesn't run.
any ideas?
Here's the code:
property fileName : "my.pdf"
set myPath to (path to me as string)
set AppleScript's text item delimiters to ":"
set the parentFolder to ¬
((text items 1 thru -2 of myPath) & "") as string
set AppleScript's text item delimiters to ""
try
set targetFile to alias (the parentFolder & fileName)
on error
return quit
end try
tell application "Finder"
open file targetFile
end tell

Answer 1

A script application is actually an application bundle - a bundle is a kind of folder that gets treated like a single item (in this case, an application). Getting path to me results in a path that ends with a colon (since it is a folder), so when you try to use text item delimiters to get the container you are actually just stripping off the trailing colon, so the path built for your file won't point to the correct location.
As previously posted, the Finder can get the container, so you can just do everything in a tell application "Finder" statement:
<pre style="
font-family: Monaco, 'Courier New', Courier, monospace;
font-size: 10px;
font-weight: normal;
margin: 0px;
padding: 5px;
border: 1px solid #000000;
width: 720px;
color: #000000;
background-color: #DAFFB6;
overflow: auto;"
title="this text can be pasted into the Script Editor">
property fileName : "my.pdf"
set myPath to (path to me)
tell application "Finder"
set the parentFolder to container of myPath
try
open file ((parentFolder as text) & fileName)
end try
end tell
</pre>