PHP新手，验证码问题

下了个开源代码研究，遇到验证码的问题，请教下，以下是错误代码：

errID:2
errStr:imagettftext() [function.imagettftext]: Problem loading glyph
errFile:IWEB_PATH/core\util\captcha_class.php
errLine:256
errTime:11-09-22 14:38:21
##出错时变量的值：##
array (
  'text' => 'nuheb',
  'fontcfg' => 
  array (
  'spacing' => 2,
  'minSize' => 22,
  'maxSize' => 24,
  'font' => 'font.ttf',
  ),
  'fontfile' => 'E:\\php\\lib\\core\\util/font.ttf',
  'lettersMissing' => 0,
  'fontSizefactor' => 1,
  'x' => 60,
  'y' => 91,
  'length' => 5,
  'i' => 0,
  'degree' => -5,
  'fontsize' => 78,
  'letter' => 'n',
)
-------

show me the code~