Cannot create child mailboxes using mavericks

Hello I have made ascript for creating parent and child mailboxes but for some reasons It cannot work

Here is my piece of script if anyone could tell me where I made a mistake?

tell application "Numbers"
	tell table 1 of sheet 1 of document 1
		set A37 to (value of cell "A37") as text --Set file name
		set A35 to (value of cell "A35") as text --Set Client folder/mailbox name
        end tell
end tell
--Create
 Mailboxes

set parentMailbox to A35
set childMailbox to A37

tell application "Mail"
	if not (exists mailbox (parentMailbox / childMailbox)) then
		set mbox to make new mailbox with properties {name:parentMailbox / childMailbox}
	end if
end tell

You’re mixing up variables names with literal strings.
A slash without quotes is the division operator

maybe

tell application "Mail"
   if not (exists mailbox (parentMailbox & "/" & childMailbox)) then
       set mbox to make new mailbox with properties {name:parentMailbox & "/" & childMailbox}
   end if
end tell

Sometimes very obvious things are blinding you…

Thanks for the help.

Hello Stefan,

For some time the script work ok but now it is broken!!!

It collects properly all information to create the parent and child mailboxes but fails to create them?

Here is the error message

tell application “Mail”
exists mailbox “ANI - International 2014-2015/ANIi14022801 - Plastic Recorder Microphone Shape M6”
→ false
make new mailbox with properties {name:“ANI - International 2014-2015/ANIi14022801 - Plastic Recorder Microphone Shape M6”}
→ error number -10000
Result:
error “Mail got an error: AppleEvent handler failed.” number -10000

Did not change anything to the script. Could it be that Mavericks broke it?