Jeff:
In addition to Wes's request for screen shots, some more information might help:
1. Are you missing the boundary in the plan and/or section window, or the boundary that shows up in the detail window?
2. If in the plan and/or section window, are you missing the editable boundary that defines the size of the detail, or the graphic boundary who's appearance is defined under the General Settings parameters for the marker.
3. Which marker are you using, are all markers acting the same way?
4. In PlotMaker, are you importing directly from the archiCAD file or creating a pmk file to bring into PlotMaker?
Hope this helps.
David