If we don't get a new file, we assume the upload failed. This is

possible when we actually don't have WRITE permission to the
'uploads/' directory.

modules/exploits/multi/http/php_volunteer_upload_exec.rb

@@ -233,7 +233,12 @@ class Metasploit3 < Msf::Exploit::Remote
 
 		# Find the filename of our uploaded shell
 		files = get_my_file(before.body, after.body)
+		if files.empty?
+			print_error("No new file(s) found. The upload probably failed.")
+			return
+		else
 			vprint_status("Found these new files: #{files.inspect}")
+		end
 
 		# There might be more than 1 new file, at least execute the first 10
 		# just to make sure.  Don't want to try too many either.