You may want to check your list of attributes or levels for a operator sign (such as > or <) in the display text. If this is the case, you need to use the equivalent html entity code instead. Below is a partial table of commonly used codes.
|ASCII Character||HTML Entity Code||Description|
A more complete list of common ASCII characters and their HTML entity equivalents is found here: http://www.freeformatter.com/html-entities.html