Script error

Your if then statements are nested in a manner that is not correct is what it is telling you.

You have an else condition after another else condition. If you want a multi-conditional argument, then you would use the elseif.

Example:

If a = b then
take action
elseif a = c then
take different action
else
take no action
end if

The "else" condition is in the event all previous arguments are not met, it will be the default answer or path it will take. From my experience programming, you only use one per "if then" loops.

In your particular case, you can close out the first else condition by simply adding end if to the script.

loop2:
VAR = 0;
VAR = getvalue(_CAN,1)'recieve the data and store in a varialbe VAR
if(VAR!=0) then 'that means you have recieved somthing
{ counter = counter + 1;
wait(datarate);
goto loop2;
}
else
{ flag = 1;
i = i + 1;
end if ' This closed out the if statement with the else condition.

' begins new if then argument

if (flag[i-1]==1 && flag[i-2]==1 && flag[i-3]==1)then '3 CONSECUTIVE missed messages_ loss of communicaiton
goto loop3;
else
{
goto loop2;
end if
}
}

loop3:
i=0;
set_command(position_feedback=0)'send a command to traction loop to zero
wait(120000) 'give the time of 2 minutes for the operator to fix the problem
goto resetval 'reset vales and start counting

If you have say 2 variables(keep things simple), and they are all integers(number values) then you can initialize those variables with 0 at the beginning of the script before the loop begins.

Example:

dim a as integer

a1 = 0
a2 = 0

'let say that a is var1 variable that changes the outcome of the above that were preset to 0.

top:
a = getvalue(_Var, 1)
if a = 1 then
a1 = 10
else
a2 = 10
end if
wait(1)
goto top

This means before it got to the top: loop label header, both of these values were initialized to 0.