Error message after upgrade - Fatal error: Access level to MCachedCore::_writeKeys() must be p

[bcdaus]

Last night I finally bit the bullet and decided to upgrade my store from 1.4.9 to 1.5.2, using the software upgrade within my hosting management system (softaculous).

 

However when I attempt to open the shop I got a blank page. I turned on debugging and now find this :

Fatal error: Access level to MCachedCore::_writeKeys() must be protected (as in class CacheCore) or weaker in /home/<WEB>/public_html/<STORENAME>/p/classes/MCached.php on line 177

 

(the bits in <> are my attempt to hide details of my server especially while the store is so broken.)

 

I get this message when accessing admin as well. I tried clearing the cache, but to no avail.

 

Any ideas ?

 

Thanks,

Bill.