Warning: Undefined variable $strTitel in /customers/b/e/1/bnv-live.be/httpd.www/pdf/tutorial/individueel.php on line 367

Fatal error: Uncaught Exception: FPDF error: Some data has already been output, can't send PDF file (output started at /customers/b/e/1/bnv-live.be/httpd.www/pdf/tutorial/individueel.php:367) in /customers/b/e/1/bnv-live.be/httpd.www/pdf/fpdf.php:271
Stack trace:
#0 /customers/b/e/1/bnv-live.be/httpd.www/pdf/fpdf.php(1049): FPDF->Error('Some data has a...')
#1 /customers/b/e/1/bnv-live.be/httpd.www/pdf/fpdf.php(999): FPDF->_checkoutput()
#2 /customers/b/e/1/bnv-live.be/httpd.www/pdf/tutorial/individueel.php(436): FPDF->Output()
#3 {main}
  thrown in /customers/b/e/1/bnv-live.be/httpd.www/pdf/fpdf.php on line 271