Transposh stdClass::$source …transposh_db.php on line 331

Hello, recently a new error message appeared on my website, for usage of transposh this is fatal:

Notice: Undefined property: stdClass::$source in /data/web/virtuals/14943/virtual/www/domains/altitudo.cz/wp-content/plugins/transposh-translation-filter-for-wordpress/wp/transposh_db.php on line 331

The other error msg that I get shown in backend only is:
Notice: unserialize() [function.unserialize]: Error at offset 0 of 504 bytes in /data/web/virtuals/14943/virtual/www/domains/altitudo.cz/wp-content/plugins/transposh-translation-filter-for-wordpress/transposh.php on line 2069

Thank you very much for any hints, how to fix this.