[TYPO3] cached pages ok, dynamic pages dead + odd mysql error: "Unable to save result set",

[Christopher]

Hello list,

I've just had a report of problems with a T3 site exhibiting the 
following symptoms:

1. Pages in the cache are all a-ok. No problems with these at all.
2. All dynamic pages either show the 'generating' message, or nothing. 
This means that, for example, pages using plugins such as tx_calendar 
and tx_indexedsearch return nothing
3. In the BE, some modules (such as Indexing > TYPO3 Pages) display a 
heap of the following error (there are more instances of this error in 
the error logs as well):

Warning: mysql_query(): Unable to save result set in 
/home/{username}/bin/typo3_src-3.8.1/t3lib/class.t3lib_db.php on line 219

Nothing unusual has happened with the TYPO3 portion of the site 
recently; editors have entered content, and nothing more.

The following steps have been taken to try to fix the problem:

1. Run repair on db tables
2. Remove cached files in /typo3conf
3. Increase memory limit in php.ini [at the host's suggestion]

Nothing has helped. Does anybody have any idea about the origin of or 
solution to the problem?


-Christopher