Hi A-Damage,
Please try demo http://www.cutesoft.net/example/general.aspx on your Mac, if it works for you, please download the latest version and try again.
Latest version downloads http://www.cutesoft.net/downloads/folders/21904/download.aspx
If you still get the same issue with the latest version, please try the solution below
1. Open file "\CuteSoft_Client\CuteEditor\Template.aspx "
2. Find section below and delete it
<link type="text/css" rel="stylesheet" href='<%=CuteEditor.EditorUtility.ProcessWebPath(Context,Page,"Load.ashx?type=style&file=SyntaxHighlighter.css")%>' />
Regards,
Ken