We are getting null pointer exception when we try to get the parent page from aPageList.
aPageList is null as the strPageListProperty is set to a dynamically created workbasket name which is not present of clipboard.
 

code below for reference.

BaseReference = D_pyWorkbasketsInMyWorkGroup.pxResults(1)

strPageListProperty = D_WorkBasket_pa3265516938292022pz.pxResults

else if("SORT".equals(gridAction) || "PAGINATE".equals(gridAction)){
String strPageListProperty = tools.getParamValue("PageListProperty");
ClipboardProperty aPageList = null;
String strBaseRef = tools.getParamValue("BaseReference");
if(strPageListProperty.startsWith(".")){
if(strBaseRef.startsWith("."))
aPageList = pgStepPage.getProperty(strBaseRef+strPageListProperty);
else
aPageList = tools.getProperty(strBaseRef+strPageListProperty);
}else {
aPageList = tools.getProperty(strPageListProperty);
}
pgStepPage = aPageList.getParentPage();
srcPage = pgStepPage;

***Updated by moderator: Lochan to update Categories and add SR Exists tag***