Severity: Warning Message: imagettftext() [function.imagettftext]: Could not read font Filename: helpers/captcha_helpe

[eluser]OKIEWARDOYO[/eluser]
i have created a captcha, it works fine on my localhost, but on my online hosting, it returns like below:

Severity: Warning

Message: imagettftext() [function.imagettftext]: Could not read font

Filename: helpers/captcha_helper.php

Line Number: 215

what does it means? and can somebody tell me how to solved it?

[eluser]Rodrigo Alexandre[/eluser]
Folder permissions have been added?

[eluser]OKIEWARDOYO[/eluser]
Folder permission for what?
for the .ttf?
or for the image where the generated imagecode saved?

[eluser]OKIEWARDOYO[/eluser]
i have set permission texb.ttf to 755, but no success, any suggestion?