Please open a Support Ticket and attach your log so that we can see what error you're getting.
It may also be useful to have a Backup of your Optional Files so that we can experiment with your custom stats directly.
Please post your ticket number here so that we can look at it ASAP.
In the meantime you can reduce the number of custom columns which are cached by disabling the "Cache" flag for some columns. Only those which have this flag enabled will be added to the cache.