Can't access admin panel for a website with CMS Made Simple: Class 'cms_cache_handler' not found

I'm working on setting up and migration of old sites to a new server from Dreamhost. I have 130 sites to migrate. 1 is successful. The version is: 1.12.1

The mods in the first site upgraded well. No problems. Have a procedure to migrate. That being said, the second site, as I followed my own documentation, fails when I try to access /admin/index.php

What I get is this below:

So, this is more informational than code... so please forgive me. I don't understand why CMS MADE SIMPLE is actually not simple.

Solution

That seems like an annoying issue. Forgive any repetition but here is what I would check:

that is is 100% functioning on existing server
correct php version 5.4.3+ (5.6+ recommended) on new server
that all files & database are copied fully & without errors
config.php settings are updated for new hosting & database
that .htaccess, php.ini/.user.ini settings are appropriate
check php error log
are there any additional modules installed that may require additional php modules
try more coffee or a nights sleep - both have helped me solve all sorts of issue in the past!
- consider posting on CMSMS forum - will get a wider range of CMSMS users/experience and suggestions

Good luck

Chris