When using Remember As to save a barrier analysis, be sure you are using a new name or TNM will overwrite your previous analysis without warning. Use File, Save or nothing will be saved on disk.
TNM dynamically links the Barrier Analysis module with TNM tables. To properly make this linkage, the Barrier view must be the active view at the time you open each results table.
Have you selected the desired receiver(s) and barrier segment(s)? If so, then also make sure that the Plan view is the active window before selecting New in the Barrier Analysis menu.
Barrier analyses, which include more than 1 barrier, will produce yellow markers for all but 1 barrier. Users should either combine barriers before performing Line-of-Sight, or perform separate analyses.