My magento site crashes daily. It comes back online after emptying the cache folder. The crash seems to be happening because the page.xml file changes the external files - js, css, images are all pointed to the default theme, whereas I use a custom theme. Could this be because of file permissions? Permissions for var and cache folder is 755.
Update: The problem is the cache file getting corrupted and the error I was getting was Front controller reached 100 router match iterations