[Scenario]

It seems like under DIALOG_REGISTER you are trying to use OnDialogReponse as a variable, not a bool.

Proper usage to check for a response is:

pawn Код:

if(response == true) // can also use if(response)

OR

pawn Код:

if(response == false) // can also use if(!response)

It's also best to use a switch statement for the list items. So for example:

pawn Код:

case DIALOG_DEFINE:
        {
            if(response)
            {
                switch(listitem)
                { 
                    case 0: // same effect as if(listitem == 0)
                    case 1: // same effect as if(listitem == 1)
                    case 2: // same effect as if(listitem == 2)
                    case 3: // same effect as if(listitem == 3)
                }
            }
        }

You can do the same with the dialog ID's, as well.