Plugins Realtime 0.5 was a problem set permissions

[ohhab]

When I click Realtime icon,It's show
"The Image Cache Directory directory does not exist. Please first create it and set permissions and then attempt to open another realtime graph."

but, In directory set permission 777
"drwxrwxrwx. 10 apache apache 4096 May 13 11:20 plugins "

In Realtime folder,
"drwxr-xr-x 2 root root 4096 Dec 22 2011 realtime"

How to solve it?