Warning multiple error (fopen, fwrite, fclose)

Hi,
I'm getting the following message on the page admin/settings/dfont after install and no fonts are rendered.
Can any one tell me what's wrong?
Thanks & Cheers.
.sahaj

warning: fopen(sites/all/modules/dfont/dfont.css) [function.fopen]: failed to open stream: Permission denied in xxx/sites/all/modules/dfont/dfont.module on line 129.
warning: fwrite(): supplied argument is not a valid stream resource in xxx/sites/all/modules/dfont/dfont.module on line 130.
warning: fwrite(): supplied argument is not a valid stream resource in xxx/sites/all/modules/dfont/dfont.module on line 142.
warning: fwrite(): supplied argument is not a valid stream resource in xxx/sites/all/modules/dfont/dfont.module on line 142.
warning: fwrite(): supplied argument is not a valid stream resource in xxx/sites/all/modules/dfont/dfont.module on line 142.
warning: fwrite(): supplied argument is not a valid stream resource in xxx/sites/all/modules/dfont/dfont.module on line 142.
warning: fclose(): supplied argument is not a valid stream resource in xxx/sites/all/modules/dfont/dfont.module on line 144.
warning: fopen(sites/all/modules/dfont/dfont.js) [function.fopen]: failed to open stream: Permission denied in xxx/sites/all/modules/dfont/dfont.module on line 149.
warning: fwrite(): supplied argument is not a valid stream resource in xxx/sites/all/modules/dfont/dfont.module on line 150.
warning: fwrite(): supplied argument is not a valid stream resource in xxx/sites/all/modules/dfont/dfont.module on line 161.
warning: fclose(): supplied argument is not a valid stream resource in xxx/sites/all/modules/dfont/dfont.module on line 162.