Do you have this code on line 143 in your blogs.php page? If so the error seems to be saying that there is output occurring on this line. You should look at the beginning and end of this line for any white space characters or returns to see if this is causing the output.
If the output has already occurred by the time to you get to this line regardless then it would be a good idea to link to the include files at the top of the page before any output occurs. You would need to make sure to adjust the paths accordingly.