The area the presents the error is ijnside the repeat block and is marked with asterisks on both ends.
tell application "Address Book"
set theGroupList to the name of the group of every person whose ((note contains "TEC TALENT") and (note contains "ID 23211"))
delete (first person whose ((note contains "TEC TALENT") and (note contains "ID 23211")))
set NewPerson to make new person
set first name of NewPerson to "Tim"
set last name of NewPerson to "eder"
set organization of NewPerson to "Sound & Light Production"
set note4 to ""
set note1 to "This entry from TEC TALENT database:ID 23211"
set note2 to "Created " & creation date of NewPerson
set note3 to "TEC Sound Production"
set note of NewPerson to note1 & note2 & return & note3 & return
if theGroupList = {} then
add NewPerson to group "TEC Talents"
else
repeat until theGroupList is {}
******add NewPerson to group (the first item of theGroupList)*******
set theGroupList to rest of theGroupList
end repeat
end if
save addressbook
end tell