I was trying some exetension, but after I installed "Ajax Search by LitExtension", my search index is broken.
Catalog Search Index says "Reindex Required". So I did.

Then I get this error. I cannot reindex it and also error message is somehow empty.

I deleted var/report as suggested here :
Catalog Search Index not changing status "required index"
but no luck.
How can I fix this? I use magento 1.8.1.0 .
I tried reindex using SSH with this
php shell/indexer.php reindexall
, then I got
PHP Fatal error: Call to a member function getReadConnection() on a non-object in /app/code/core/Mage/Core/Model/Resource/Db/Co llection/Abstract.php on line 134
– Aug 08 '14 at 09:37Fatal error: Call to a member function getReadConnection() on a non-object in /app/code/core/Mage/Core/Model/Resource/Db/Collect ion/Abstract.php on line 134
– Aug 08 '14 at 09:37However, search index is still not working.
– Aug 08 '14 at 10:09