If you still have problems getting the thumbnail automatic generation working, please read this tutorial. I spent a lot of my time creating this tutorial, including screen shots for some significant steps, and adding narrative text to each image. Please consider reading the whole instruction again, again, and again because I found out that there is 90% possibility that you missed one spot and there are many occurrences one say that he/she did not missed anything but ended up saying “Ah, yeah, I forgot that one.” :D
The CHMOD 777
Upload and activate the Arthemia theme. Then, the first step is to make the
cache folder writable. You can either try ’777′ writable or ’755′ writable. Some web hosting company prevent you making any folder ’777′ writable due to some security reasons. But, I suggest you to try with ’777′ writable first. I use FileZilla to do the FTP work because it is free and has a lot of features. To make the folders writable, simply right click the folder name and select ‘File Attributes’ and a dialog box will show up.