php error happened

Technical information
Error type8
Error descriptionArray to string conversion
URLwebdesign.wd22.com/Promotions_list.php?
Error file/home/wd22com/public_html/webdesign/classes/runnerpage.php
Error line707
SQL querySELECT Service, Image, Description, Price, ID FROM `_promotions` ORDER BY 5 ASC

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