You have a pretty high CM rating so if you study courses that are rated below that, you won't get points. You're like 18something on CM so to give an extreme example, if you were studying a beginner course rated 1000 then it really wouldn't be fair to give you additional points for a course far below your rated ability. Hope that made sense. Try a really tough course like Silman's "Elements of positional understanding" and you'll see your rating change.
EDIT "Roots of Positional Understanding"
.. but these r the ones I have been and am currently doing,mostly Karpov's,Anand's ,etc Games ,all 2000 plus rated .. earlier,I got points but not now .. I chose the 'Adaptive' Setting ie,to find problems near my Rating.
.. n' also they r First Attempt/New Lessons.
.. Tnx.
Sorry but I don't use adaptive or sequential; I just pick a course I'm interested in and do the lessons. Oh well, best of luck and hopefully someone else will read of your plight and shed some light on the situation.
Pardon me if what I'm asking seems silly, but you aren't by any chance reviewing previous lessons and expecting to get more points are you? It is of course recommended that you do the lessons multiple times, but points are only available the first time through. Whoops, you just answered that in which case I am officially clueless. Sorry I couildn't help.
No,act i juz edited my post to add this point .. I'm referring to First Attempt /New Lessons .
I know if u r reviewing old ones/that u hv done before( 2nd Attempt,etc ),u don't get points .
Tnx Anyways,baddogno.
Yeah,I edited it at the same time it occurred to u .. lol
They probably wont respond here, send in a ticket.
http://support.chess.com/Tickets/Submit
The rating is a useless number anyway, completely dependant on the courses you do.
Ok,I juz tried doing 2 more n' now I'm getting points again for my 2nd one but not for the first one ( tho both 100% correct ) :
I think my Setting got changed somehow ( dunno how or why) n' it went to some other Lessons that were probably much Lower Rated so I didn't get any points for those ,juz as baddogno explained earlier.( tho I did click on 'Settings' n' chose 'Adaptive',then clicked on 'Save' each time ) but now it's back to 'Adaptive' .. Yay !
Tnx for the Explanations,Everyone ! 
My Chess Mentor Rating is not increasing again although I got 100% correct for my last 2 Lessons and 60% for another one .. It doesn't even say 0% increase .. only the Rating Bar is there showing 100% but my Rating remains the same.
Why is this so ( Is this a bug ? ) n' How do I get it to work like before ?
I clicked on 'Settings' tab but there's nothing there.
( I do not want to reset my Rating n' History ; I want to continue with my current one )
{ It happened before,but was ok already n' now it is happening again }
Tnx So Much !