According to : http://msdn.microsoft.com/en-us/library/ms175061.aspx It says that the "NOT LIKE" relational operator : "Specifies that the trace event data must not be like the text entered. Allows multiple values."
But HOW do you specify multiple values ?
Never mind, figured it out. After you have typed in one value, press ENTER at the end of the textbox. This causes another textbox to be shown under the current one, into which you can type an additional value.