Resize doesn't work

Hi, when i add the resize option, it show me an error:
<h1>A TimThumb error has occured</h1>The following error(s) occured:<br /><ul><li>Could not create the index.html file - to fix this create an empty file named index.html file in the cache directory.</li><li>Could not create cache clean timestamp file.</li><li>Could not find the internal image you specified.</li></ul><br /><br />Query String : zc=0&cc=&src=wp-content/gallery/the-hostal-rooms-apartments/ba_o_diablito.jpg<br />TimThumb version : 2.8.11</pre>
The cache has 775 permission and nothing happened.
Can someone tell me a tip?
🙂
Thanks

Mario

http://wordpress.org/extend/plugins/nextgen-nivoslider/