Zeroed out work - Challenge for experts, Whats the problem?

[David]

So my schedule has been going ok for a month or so. This is a large schedule
with about 2000 lines.

I am having the following problems.

1. The duration and work of tasks get zeroed out for some reason.
2. Task finish dates change to some odd date. e.g. the task is only
tasking 36
hours, but the duration is 266 days.
3. Completed tasks show 0 BCWP

This is assuming I do not have autoleveling enabled. Also that no one has
manually set the work or duration to zero and that a baseline has been
established with non zero values.

I need help!!!

David