My file is old and TaskStart/TaskEnd were not working correctly with gantt charts.I removed the equations as Pierre instructed. I can now enter the start dates and end dates correctly. There are still problems.
1. Enter a TLI. No dates.
2. Create a sub item with start date and end date. The gantt bar displays correctly and the TLI (summary bar) updates to reflect the total duration of its child. But, the TaskDuration field is blank for both the TLI and this sub item
3. Now enter another sub as a sibling of the first sub. Enter start and end dates. Now create a dependency from the first child to the second child (sibling). See?