Error when executing a Client Tag Change script

Ignition
1

Error message:
Error executing tag change script. Tag event received for unknown property. Path: [client]tagname, property: Value
The script is executed though.

2

post your script inside triple back quotes(above the tab key). Having script posted is always a helpful thing. My first impression is that Value needs to be value.

3 
from time import sleep
ClientTagsFolder = Util.LocatieClienttags()
qv = system.tag.read( ClientTagsFolder + 'OpenPopupTimer' ) // trigger tag script
Teller = qv.value
print Teller
if( Teller > 0 ):
	Teller = Teller - 1
	system.tag.write( ClientTagsFolder + 'OpenPopupTimer', Teller )
	sleep( 1 )
if( Teller == 0 ):
	qv = system.tag.read( ClientTagsFolder + 'OpenPopup' )
	Popuppath = qv.value
	system.nav.closeWindow( Popuppath )