- I have already contacted the mod auther but after looking around the error can be caused in various mods.
I just ran Add changes from Prosilver to my theme and now,
Fatal error: Cannot redeclare cache::obtain_points_config() in *****/includes/cache.php on line 89
And now Everything has locked out with that error, including the ACP
The error message indicates that you have made changes to includes/cache.php as part of installing whatever Points System MOD you are using. So it is, as you said, a problem with that MOD, and not a general problem with phpBB.
Since there is no MOD support in this section of the support forum, you'll need to get help from the MOD author.