Not sure how serious this is. First time I have turned on debug.
Downloaded new complete package. Admin says Moodle 1.6.2+ (2006050521). Changed a few settings in my first lesson. and said yes to use this as a template. I first saw 5 lines of error code. Good news is that it seems to have saved the lesson settings when I created a second lesson.
Here is what flashed.
Notice:Undefined Property: stdClass:$name in G:\xampplite\moodle\mod\lesson\lib.php on line 191.
similar for $name on line 192
similar for $available on line 199
similar for $deadline on line 201
similar for $available on line 201