Preload doesn't preload all my posts!

Hello! I am trying to preload my posts with the preload tab and although everything seems to run ok, it stops preloading before caching all my posts. I currently have 64 pages that i need to preload. First time it preloaded 34 out of 64. Second try and it preloaded 49 out of 64! It looks like it will preload different amount every time i run it! Is there something wrong? I would like to preload all of my posts (64/64).Thanks in advance for any answer!

http://wordpress.org/plugins/wp-super-cache/