tool change

Hi 
After a couple of years of not working wih my cnc i rebuid the machine and installed a new version of linuxcnc. (2.
Since then I have had a lot of problems with getting things to work. 
One of them is getting the toolchange to work in gmocappy.

I followed the online manual and at some point you have to copy some python files from the sim folder to the machine folder. I couldn't find the sim folder anywhere so I downloaded the (latests) files from Github.

The change of a tool and measuring procedure seems to work ok. In Gmocappy screen I press the T? M6 button and select another tool. 
The spindle moves to the change position and after klicking ok it moves down to the sensor position. 
Soon as it touches the machine stops and shows the next error:

"Unknown word where unary operation could be" 

I allready added % signs in the change.ngc file otherwise it would give a operator error.

I had to comment out the tool change lines in Piedras.hal to get stuff to work.

i have attached some of my files. I am completely new to Linux and programming so bear with me.
Can you point me in the right direction?

Does it say on which line the error is found?

i see several instances of
And I am fairly sure that needs to be
ie, return from the <change> subroutine, not return from the Onnn IF.

I think this might be the problem:

"This" will be interpreted as a tool number command....

Wel that was easy 
a simple ; does the trick

now into tuning the machine 

I didn’t need to edit the other blocks by the way

Clements wrote:

I didn’t need to edit the other blocks by the way

It might work now, but it shouldn't. I wouldn't suggest relying on it working like that indefinitely. 

with a manual toolchange is works but I am running into some errors when a tool change is called in de g-code
I'll start with your suggestion