[TYPO3-Solr] solr 3.0.0 problems after upgrading to typo3 6.2.4

[Jan Slusarczyk]

> please check this: https://forge.typo3.org/issues/44378
>
> we have it running with TYPO3 CMS 4.5.x and ubuntu 10.04
> and also with TYPO3 CMS 6.2.x and ubutun 14.04.

But this forge issue is related to php version <= 5.3.7. I'm on 5.3.10 
which is newer... Also solr was working fine before the upgrade to typo3 
6.2.4...

I've made some more tests and it seems that solr works sometimes... 
First request generates the content, each consecutive generates error 
exception. I have no idea how to debug this further - I am overwhelmed 
by the upgrade so far...

Jan