Dear Jaewon,

Could you please suggest a method for saving the getkeypress outputs as user variables, including the scanecode and rt?

Use bhv_variable().
https://monkeylogic.nimh.nih.gov/docs_RuntimeFunctions.html#bhv_variable

I did as you suggested, but the error message still appears.

Kindly look at the picture that is attached.

Following to the above image, I run the script where I put getkeypress function in the userloop function and an error is shown again.

For the error, kindly look at the picture attached.

Obviously you tried to save a variable that did not exist. Place bhv_variable() at the end of the script or after the variable is created.

Timing script functions are available only in the timing script. I do not know why you want to get a key input in the userloop, but you need to use a different method to do so. Please read the manual, if you did not.
https://monkeylogic.nimh.nih.gov/docs_CreatingTask.html#RuntimeVersion1

Thanks for the response; the Problem is solved.