Symptoms of a corrupted file: handles do no appear for selected objects, drawing size increases to the maximum size for no apparent reason and objects do not delete. A file will become corrupted if the following steps are applied: Create a new document, add a circle and place a circle center on it. Immediately save the document, close and re-open it. Now try moving the circle center. You should get an "Objects must be contained within boundaries" message. At this point the file is corrupted. What has happened is that 4 objects have been written to the file out of the file's boundaries.
SOLUTION: Use Claris CAD 1.0v3. The first time you open the file in 1.0v3, delete all circle centers, copy the remainder of the drawing into a new file. Now, recreate the circle centers. Everything should now be OK.