dx_auth unlink error

[eluser]Niraj Dave[/eluser]
please help...

after disable javascript in browser, captcha works perfact.

but by enable javascript, error is

ERROR - 2009-11-12 08:18:17 --&gt; Severity: Warning --&gt; unlink(./captcha/fonts) [<a href='function.unlink'>function.unlink</a>]: Is a directory html/ci/system/application/plugins/dx_captcha_pi.php 258

ERROR - 2009-11-12 08:18:17 --&gt; Severity: Warning --&gt; unlink(./captcha/.svn) [<a href='function.unlink'>function.unlink</a>]: Is a directory html/ci/system/application/plugins/dx_captcha_pi.php 258

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is it really permission problem ?

please give me solution ....