your script doesn't run on my machine either (Mac OS X 10.6.8 AppleScript Editor).
get properties of static text 1 of group 3 of window 1 of process "Safari"
--> error number -1719 from «class sgrp» 3 of window 1 of «class prcs» "Safari"
keystroke "/" using command down
get properties of static text 1 of group 3 of window 1 of process "Safari"
--> error number -1719 from «class sttx» 1 of «class sgrp» 3 of window 1 of «class prcs» "Safari"
keystroke "/" using command down
tell application "System Events"
set statusLineThere to true
tell process "Safari"
tell front window
try
properties of group 3
on error
set statusLineThere to false
end try
end tell
end tell
end tell
statusLineThere