Please help me in this .
Tell me how to remove this error
Hi,
Welcome to the forum.
Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.
Also what model Arduino are you using?
Thanks... Tom... 
First question is what you're trying to do when the message occurs? Upload?
If so, did you select the correct board and the correct port in the IDE's tools menu?
Which OS are you using and which version of the IDE?
Which board are you using? Clone or original? For a clone, you might have a board with a CH340 chip and under windows (and maybe other OSes as well), you will need the CH340 driver.
// Edit:
Useful links:
https://www.arduino.cc/en/Guide/Troubleshooting#upload
http://forum.arduino.cc/index.php?topic=73748.0
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