You can simply use code-tags when posting code (no need to post plain-text or images of code or both). You can also go back and just edit your first post too to include them.
If you are reporting an error, report it in full including the line/column number reported with it and if it’s not identical to the code you’re posting then indicate which line it is.
You can also look up the error with Google which is easy to do. To be honest, the error is pretty self explanatory. You need to assign whatever it is you’re assigning to what it says, a variable, property or indexer. It might be that on the line/column is actually gives you, you didn’t mean to assign anything which I think is the case here.
I can see you typed “istouching = true” but presume you mean to use “==”.