You have the model located at a great distance from the origin, and this creates a lot of problems and sometimes in conjunction with other modeling mistakes it generates various errors (such as the one you ran into).
Also:
- learn to Purge;
- learn to group each element separately, don’t leave loose geometry;
- do not import components from 3D Warehouse directly into the model you are working on.
To start solving the problem:
- convert the four groups (with their subgroups) into components and save them separately. Then delete them from the model and Purge;
- Zoom Extents (Shift + Z) and you will see the model;
- Import back the 4 groups that you checked, scaled and cleaned before. If you resize a component (from the outside), make sure you apply the new scale (Scale Definition);
- reposition it to the origin.
