Dashboard | Indicator spinner spins indefinitely - caused by exception "Cannot invoke method sort() on null object"

[jmiranda]

2013-10-15 21:11:31,932 ERROR  GrailsExceptionResolver - Exception occurred when processing request: [GET] /openboxes/json/getDashboardAlerts
Stacktrace follows:
java.lang.NullPointerException: Cannot invoke method sort() on null object
        at org.pih.warehouse.inventory.InventoryService.getQuantityByProductAndInventoryItemMap(InventoryService.groovy:1087)
        at org.pih.warehouse.inventory.InventoryService$getQuantityByProductAndInventoryItemMap.callCurrent(Unknown Source)
        at org.pih.warehouse.inventory.InventoryService.getQuantityByProductMap(InventoryService.groovy:1161)
        at org.pih.warehouse.inventory.InventoryService$getQuantityByProductMap.callCurrent(Unknown Source)
        at org.pih.warehouse.inventory.InventoryService.getDashboardAlerts(InventoryService.groovy:705)
        at org.pih.warehouse.inventory.InventoryService$$FastClassByCGLIB$$a7f866ff.invoke(<generated>)
        at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
        at org.pih.warehouse.inventory.InventoryService$$EnhancerByCGLIB$$f5314030.getDashboardAlerts(<generated>)
        at org.pih.warehouse.inventory.InventoryService$getDashboardAlerts.call(Unknown Source)
        at org.pih.warehouse.JsonController$_closure10.doCall(JsonController.groovy:226)
        at org.pih.warehouse.JsonController$_closure10.doCall(JsonController.groovy)

        at grails.plugin.springcache.web.GrailsFragmentCachingFilter.buildPage(GrailsFragmentCachingFilter.groovy:152)
        at grails.plugin.springcache.web.GrailsFragmentCachingFilter.buildPageInfo(GrailsFragmentCachingFilter.groovy:93)
        at grails.plugin.springcache.web.GrailsFragmentCachingFilter.doFilter(GrailsFragmentCachingFilter.groovy:62)
        at net.sf.ehcache.constructs.web.filter.Filter.doFilter(Filter.java:86)
        at java.lang.Thread.run(Thread.java:744)