[TYPO3-Solr] a lot of failures

[Hans-Peter M.]

Hello list,

i start a new attempt to bring t3-solr up and running.
The index queue worker shows a lot of failures and indexed only 7%.

The Logfile shows:

Administrationlog
Core: Error handler (FE): PHP Warning: json_encode(): Invalid UTF-8
sequence in argument
in 
.../typo3conf/ext/solr/classes/indexqueue/class.tx_solr_indexqueue_pageindexerresponse.php
  line 117
Core: Error handler (FE): PHP Warning: json_encode(): Invalid UTF-8
sequence in argument
in 
.../typo3conf/ext/solr/classes/indexqueue/class.tx_solr_indexqueue_pageindexerresponse.php
  line 117
Core: Error handler (FE): PHP Warning: htmlspecialchars(): Invalid
multibyte sequence in argument
in .../typo3conf/ext/solr/lib/SolrPhpClient/Apache/Solr/Service.php
  line 817

Developerlog:
code 1331837081
message Failed indexing page Index Queue item 3092


I use typo3 4.5, templatevoila 1.7.0 and solr 2.8.0

How can i get troubleshooting further?

regards
manne