Fixed in version 3.2.x
After upgrading from MediaWiki 1.24.x to 1.26.2, I started noticing that some pages just plain wouldn't load, with an accompanying Apache error log messageː
"Call to protected method DatabaseBase::ignoreErrors()"
I fixed this by commenting out the method call in PubmedParser.Core.php on line 233.
Dave
My apologies for not responding for so long. For whatever reason I was not notified of your comment -- funnily, I stumbled upon it after upgrading my own Wiki to 1.26.x, encountering the error and googling it ... ;-) I'll look into it, i.e. try to remember what the purpose of ignoreErrors was in this context.