I am trying to compile an application optimized and gives me the same mistake in different lines, but it is always the same CS1056: C character 'i' unexpected.
Sub txtFiltCli_KeyPress (key)
timer4.Enabled= true
That "i" is not the real problem. Just that sub on it's own compiles fine for me. That error must be caused by something else elsewhere in your code. If you post some code that causes the error I will try to track it down for you.