MacBook Air restart message

I am using a late 2010 MacBook Air now updated to OSX Mountain Lion (10.8.2. Version). It works great but since I have updated it to OSX Mountain Lion I am having the following problem:

1.- I work as usual with my MBA and when my work is finished I shut it down normally, closing first all the opened apps (the shut down from the Apple menu located at the top left corner of the screen).

2.- When I turn on my MBA again (form example at the next day or a few hours later and I introduce my password) a lot of letters and words appear in my screen (over a black canvas) and then a message saying "Your computer was restarted because of a problem. Press any key to restart it or wait a few seconds" (something like that). Then appears a report and the MBA says that it will be sent automatically to apple. It happens everyday.

3.- So, I have to wait some seconds and this cause that the starting time of my MBA had increased too much, even I have to introduce my password again for restarting my MBA.

Can anybody knows the solution to this concern and provide me advice or help? thank you very much in advance !!