Memory Cache : functions are missing
Installation and Configuration
Send us your login details and we'll take a look. There's nothing else to advise.
If you want to clear your caches manually, there is a method here:
https://www.jamroom.net/the-jamroom-network/documentation/troubleshooting/114/somethings-wrong-what-do-i-do#manually-clearing-caches
And another thing to check would be to see if the same issue exists when you use a non custom skin.