Hi I'm just wondering if anyone has come across this error when installing a site:

I've tried to upload enhancements to a site that i've created previously for a client (replace bin and templates), but I get the error above when accessing it.  I'm trying to determine the differences in environment... has anyone come across a similar error?  

NB: Obviously when I deploy to my dev and test sites the site is fine, and even taking a copy of the clients webroot and database locally I am able to deploy successfully.