[solved] Help on counterbalancing icon position, expected responses and a non solved error

Hello,

I started to learn and use OpenSesame this year to make a program for the experiment I created for my research project so I'm still learning how to use OpenSesame.
I have two questions about my program and I encountered an error which I don't understand and I hope someone here will be able to help me:

I can also post my questions in french so feel free to ask if you want:

First a presentation of my experiment to help you understand my questions:
The participants have to implicitly memorize 88 object pictures (encoding session) in two conditions (manipulation and rotation).
Then they have to remember the former pictures mixed with 88 new ones (recall session) either with a concordant cue (same condition than the encoding session) or a non concordant cue (the other condition))
I created 8 lists of object pictures to counterbalance the item repartition between the conditions.
During the encoding session, the subjects will have to indicate with the "l" or "s" keys:
-for the manipulation condition: How many hands do they use to interact with the object (1hand icon ou 2hand icon)
Even if there is no properly speaking correct response for this condition, I know what should respond the subject thanks to some pre tests that I made on 20 subjects.
-for the rotation condition: Make a mental rotation of 90° on the right of the object and indicate which of the two icons corresponds to this rotation. There is a correct response for this condition: the rotation on the right

During the recall session the subjects are presented former objects ou new ones. The participants have to:
1-Indicate if the object is former ou new (there is a correct response)
2-Indicate their level of certitude with respect to their response former/new (there is no correct response)

Now about the error I encountered: Here's the image of the error message that appears. I don't understand where is the error and how to correct it:

And my two questions:
Until now the program was at its tests phase so I didn't counterbalanced the icon position for my two conditions (rotation and manipulation)
So I tried to and I think I have found a way to do it:
I defined a variable "position_icone" which represents the position (in abscisse) of the right rotation icon ou the 1 hand icon according to the condition
In the sketchpad I inserted:
-for the right rotation icon/1hand icon: the variable [position_icone]
-for the left rotation icon/2hands icon: the variable -[position_icone]
--> is it a good way to counterbalance the icon positions?

If yes there is for the moment a problem about the response that we expect the subject will make (l or s)
-during the encoding session it changes depending on the items (because the icons are counterbalanced)
-during the recall session (former/new response) it changes because of the aleatory repartition of the former and new items in the list
So I tried to create a simple way for me to know if the participant answered as expected or not:
I defined a variable "rep_att" which represents the response that we expect of the subject depending on the item. But I don't know how to make it match the subject response:
=>Would it be a solution to insert in the response sketchpads the variable [rep_att] within the tab "correct response"? Or is it simpler to match the expected responses and actual responses on Excell once the responses collected by checking if it's the same or different?

Thank you in advance for your responses!
Regards,
Mathurin Tiffany