Warning message on search results page

Hi,
I’m using wpsolr plugin in my localhost but I’m getting below warning message on search results page. Could you please advise me to fix this?

versions I’m using
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wordpress – 4.2.2
OS – windows 8
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Warning: session_start(): Cannot send session cache limiter – headers already sent (output started at C:\xampp\htdocs\wordpress\wp-includes\class.wp-styles.php:125) in C:\xampp\htdocs\wordpress\wp-content\plugins\wpsolr-search-engine\ajax_solr_services.php on line 22

https://www.ads-software.com/plugins/wpsolr-search-engine/