after instaling sdk 6.2 i get "Undefined symbol "myFunction" detected" in all my codes and i cannot compile

BUILD: ERROR: E:\Create\Garmin\BigHeart2.0\source\BigHeartView.mc:61,3:  Undefined symbol ':dc' detected.

if i declare : var dc=null; 

i get: 

BUILD: ERROR: E:\Create\Garmin\BigHeart2.0\source\BigHeartView.mc:97,3:  Invalid '$.Toybox.Lang.Number' passed as parameter 2 of type '$.Toybox.Time.DateFormat'.