Desperately need help :/

Copy/pasting code can be problematic if you’re using a Rich Text editor or copying from a web page; if you paste in tag delimiters it will often convert these to html enitities, or what you copy may actually be html entities that were converted by the browser, and thus instead of being recognized by the parser (and this includes the browser’s parsing of < and > tags, not just MODx parsing of [ and ] tags) it will be displayed.