I have set up a wordpress website on amazon ec2 using ubuntu 1.04 LTS by following this tutorial end to end except that i used amazon RDS(thier cloud database service) instead of sql.Although i dont think using RDS instad of mysql could have caused the problem. But I do think you ll need to check this tutorial out before you can answer the question.
The wordpress installation works file but when i try to install a new theme or new plugin from the admin panel i get the following error
Unable to create directory wp-content/uploads. Is its parent directory writable by the server?
i even created the uploads driectory manually from terminal and then got the follwing error
The uploaded file could not be moved to /home/ubuntu/www/wp-content/uploads.
i was pretty sure it had something to do with the file and folder permissions ao i used the following commands
find /home/YOUR_USER_NAME/www/html/ -type d -exec chmod 755 {} \;
find /home/YOUR_USER_NAME/www/html/ -type f -exec chmod 644 {} \;
to set every folder to permision to 755 and file to 644 respectively but still no help i have trying to fix this for more than 2 days now without a solution. Please help! P.S.> i have wordpress3.5 , ubuntu server 12.04