Basic code, strange errors

[computermouse]

I wanted to creat a script that would forbid people from placing a block, messaging 'It's not allowed to place a block.' This is what I wrote.

My codes:

on place:
        message "It's not allowed to place a block"
        cancel event

This is a very basic set of codes as you see, but when I tried to reload the file but there came an error!
It said

Line 2: (블럭설치.sk)
There are multiple command senders in an on place event. You must define which command sender to use.
Line: message "It's not allowed to place a block"

[Skript] Encountered 1 error while reloading 블럭설치.sk! (27ms)

Never mind "블럭설치". It's just the name of the script file.
I guessed that maybe 'message' keward should be related to the error so I changed it into 'broadcast' and it worked without an error!


So, I guess 'message' caused this error. Please tell me what is the problem exactly and what should I do to solve this situation.
In addition, my skript plugin's version is 2.8.2

 

[Im8bit]

do message "It's not allowed to place a block" to player

 

[computermouse]

do message "It's not allowed to place a block" to player

Wow It works! Thank you so much!! BTW, I saw a skript lesson video in youtube to learn skript and there, he wrote the codes as I did but in his case, it worked! Can you tell me what's the difference? Is it the difference of the version? Maybe my skript version has been updated to put receiver at the end of the 'message' codes?