What Luke said.

"You cannot, in general, place a variable declaration in a begin
scope and use it in the ensure scope unless you use nil?. It is
better to swap line 35 and line 34."

modules/auxiliary/analyze/jtr_aix.rb

@@ -31,9 +31,8 @@ class Metasploit3 < Msf::Auxiliary
 	end
 
 	def run
+		wordlist = Rex::Quickfile.new("jtrtmp")
 		begin
-			wordlist = Rex::Quickfile.new("jtrtmp")
-
 			wordlist.write( build_seed().join("\n") + "\n" )
 		ensure
 			wordlist.close