My site is not receiving any clicks suddenly, I don't know why, it was receiving around 15 clicks daily but now a days it is not receiving the clicks, what would be problem?

hi.
May be your site is blocked by Google so make report to the webmasters.

Possible reasons,
-You might have clicked your own ads
-You might have placed AdSense code on pages

Refer to this AdSense program policies to ensure you haven't violated them,
http://support.google.com/adsense/bin/answer.py?hl=en&answer=48182

might be blocked?

If you have Norton Anti-Virus email scan running, you are getting the error because Outlook Express is trying to download a message with improperly formatted headers. Most typically, it is a spam. And most of the time the cause is the headers are not properly separated from the message body by two line breaks.If you do not have Norton Anti-Virus email scan running, then never mind.

hi.
Make a report to Google regarding this may be Google has banned your site.

If you have Norton Anti-Virus email scan running, you are getting the error because Outlook Express is trying to download a message with improperly formatted headers. Most typically, it is a spam. And most of the time the cause is the headers are not properly separated from the message body by two line breaks.If you do not have Norton Anti-Virus email scan running, then never mind.