XF 1.5 Odd server error

[Stuart Wright]

Upgraded to 1.5.6 early this morning on our live server. All went well. https://www.avforums.com
Went to edit a template this afternoon. It saved ok. Reloaded ok. Looked perfect. But the change didn't appear on the live site. Very frustrating and can't figure out why.
Went to the admin home and got the message There are manual rebuild processes that have been stopped before completion. Click here to complete them, so I clicked to continue and got this server error:

Server Error
file_exists(): open_basedir restriction in effect. File(/home/sites/sandbox/public_html/install/data/templates.xml) is not within the allowed path(s): (/tmp:/usr/share/pear:/usr/share/php:/home/sites/php-session:/home/sites/avforums/:/home/sites/avpodcast/public_html/:/usr/share/GeoIP/)

1. XenForo_Application::handlePhpError()
2. file_exists() in Zend/Xml/Security.php at line 93
3. Zend_Xml_Security::scanFile() in XenForo/Helper/DevelopmentXml.php at line 17
4. XenForo_Helper_DevelopmentXml::scanFile() in XenForo/Deferred/ImportTemplate.php at line 16
5. XenForo_Deferred_ImportTemplate->execute() in XenForo/Deferred/Atomic.php at line 66
6. XenForo_Deferred_Atomic->execute() in XenForo/Model/Deferred.php at line 295
7. XenForo_Model_Deferred->runDeferred() in XenForo/Model/Deferred.php at line 429
8. XenForo_Model_Deferred->_runInternal() in XenForo/Model/Deferred.php at line 374
9. XenForo_Model_Deferred->run() in XenForo/ControllerAdmin/Tools.php at line 159
10. XenForo_ControllerAdmin_Tools->actionRunDeferred() in XenForo/FrontController.php at line 351
11. XenForo_FrontController->dispatch() in XenForo/FrontController.php at line 134
12. XenForo_FrontController->run() in /home/sites/avforums/public_html/admin.php at line 13

Now /sandbox/ should have nothing to do with anything on the live server so I'm confused.
I keep getting the menual rebuild process message and keep getting the server error.

Now this might be totally irrelevant, but our sandbox (at sandbox.avforums.com) has recently been upgraded to php7 for testing and mid morning my hosts copied our live site over afresh. When I visited the sandbox it said an upgrade was pending and I clicked to continue and it completed the 1.5.6 upgrade. Which I thought was odd because the copy, I thought, was of the live site after upgrading.

I think the problem is on the live site somewhere. Any ideas where to look for the solution?
Many thanks.

 

[Stuart Wright]

It's been suggested that the sandbox was accessed before the memcache settings were removed, hence using the live server memcache settings. Could this produce the server error above on the live server?

 

[Mike]

I don't think this particular error would be from that -- if there was some sort of symlink, I could see this happening. But two distinct sites pointing to the same cache will cause problems and unexpected errors.

 

[Stuart Wright]

My host cancelled all the outstanding processes.
I then still couldn't get changes to a particular template to appear on the website until I upgraded an addon which rebuilt all the templates, and the problem is now fixed.
Thanks