🚀 go-pugleaf

I'm working on a telephone book which has 8-digit numbers. The file I rec'd has all 8 digits in a contiguous row, but I needed to insert a space in the middle, i.e. change from  
 
12345678 
 
to 
 
1234 5678 
 

After some trial and error I came up with this: 
 
tell application "InDesign 2.0" 
	if (count documents) > 0 then 
		set find preferences to nothing 
		set change preferences to nothing 
		set myDocument to active document 
		tell myDocument 
			set myFoundItems to {} 
			set myFoundItems to search myDocument with find attributes {whole word:true, applied character style:character style "Number" of myDocument, find text:"^9^9^9^9^9^9^9^9"} 
			try 
				myFoundItems 
			on error 
				set myFoundItems to {} 
			end try 
			if (count myFoundItems) > 0 then 
				repeat with myCounter from (count myFoundItems) to 1 by -1 
					set myFoundItem to item myCounter of myFoundItems 
					set contents of insertion point -5 of myFoundItem to space 
				end repeat 
			else 
				activate 
				display dialog "Specified Text Not Found" 
			end if 
		end tell 
	else 
		activate 
		display dialog "Please open a document and try again." 
	end if 
end tell 
 

My questions are: 

1) Can somebody explain the myCountItems routine? I've just cut-&-pasted it, but I don't understand it. 

2) Why "insertion point -5"? I found it though trial and error, but I don't understand the logic. 

3) Is there a more elegant way to do my error-checking? 

Thanks to all previous posters from whom I borrowed in order to do this. 

Jay