If you have events that are taking mouse and touch input they can mess each other up. To fix it select the touch object in your object list to bring up the properties and un-check Use Mouse Input. Other than that it is as simple as Jobel as said.
Assign the object a Boolean Instance Variable.
Then in the events do an On object touched-Toggle Boolean.
Run in Debug with the object selected so you can make sure the Instance Variable is being toggled. It should be switching from 1 to 0.
If that is working you know the touch events work.
All else fails upload a .capx to a dropbox and share a public link so people can take a gander at what is exactly going on in your code.