Renaming a file in Finder changed with Snow Leopard somehow?

Question

I've used an AppleScript for ages to:
1. choose a file (a screenshot)
2. prompt for a new name
3. File is renamed by Finder with new name
4. compose a command to copy it to another server
It seems Finder is not updating the "alias" to the file since I upgraded to Snow Leopard; this very code has worked for the last few versions of OS X:
set screencap to (choose file with prompt "Choose the screen shot: ")
display dialog "Enter new file name: " default answer "foo"
set newname to (the text returned of result as string)
set newnamepng to (newname as string) & ".png"
log "newname is " & newname & " newnamepng is " & newnamepng
log "screencap is " & screencap
tell application "Finder"
set the name of screencap to (newnamepng as string)
end tell
log "the name of screencap is now: " & screencap
set posixscreencap to the POSIX path of screencap
set scpcmd to "scp " & posixscreencap
log scpcmd
Here's what happens when I run it:
tell application "AppleScript Editor"
choose file with prompt "Choose the screen shot: "
--> alias "Einny:Users:swain:Desktop:Screen shot 2010-09-13 at 2.06.44 PM.png"
display dialog "Enter new file name: " default answer "foo"
--> {text returned:"newnameforscreenshot", button returned:"OK"}
end tell
(*newname is newnameforscreenshot newnamepng is newnameforscreenshot.png*)
(*screencap is Einny:Users:swain:Desktop:Screen shot 2010-09-13 at 2.06.44 PM.png*)
tell application "Finder"
set name of alias "Einny:Users:swain:Desktop:Screen shot 2010-09-13 at 2.06.44 PM.png" to "newnameforscreenshot.png"
--> "newnameforscreenshot.png"
end tell
(*the name of screencap is now: Einny:Users:swain:Desktop:Screen shot 2010-09-13 at 2.06.44 PM.png*)
(*scp /Users/swain/Desktop/Screen shot 2010-09-13 at 2.06.44 PM.png*)
For some reason the file alias "screencap" does not get a new name. Any suggestions?

Answer 1

When I run your script, the file name does get changed, it is just that the Finder is not keeping up with the script. There are a few fixes:
1) add a short delay after the rename (delay 1 seems to be enough)
2) use *System Events* instead of the Finder
3) add an update command after setting the name in your FInder tell statement (e.g. update screencap)
Note that an alias will still point to the same file item (even if it does have a different name), but the POSIX path of the alias object does need to be updated before you can use that.