@ProspektThere are ways to traverse up and down the DOM using xpath. To retrieve the parent TR element, you should be able to do this --
$sRowTask = _WD_FindElement($sSession, $_WD_LOCATOR_ByXPath, "//td[contains(text(),'入庫データ取込エラー対応')]/parent::node()")
There are additional ways to achieve the same result. Here's another option --
$sRowTask = _WD_FindElement($sSession, $_WD_LOCATOR_ByXPath, "//tr[./td[contains(text(),'入庫データ取込エラー対応')]]")