[Uleat]

If you're still willing to pare this down, revert your source code and try this one:

[Item.cpp.patch]

Index: common/Item.cpp
===================================================================
--- common/Item.cpp	(revision 2284)
+++ common/Item.cpp	(working copy)
@@ -1216,6 +1216,14 @@
 	else {
 		// Slot must be within a bag
 		ItemInst* baginst = GetItem(Inventory::CalcSlotId(slot_id)); // Get parent bag
+
+		if (baginst) {
+			LogFile->write(EQEMuLog::Error, "Inventory::_PutItem: Parent Bag: id = %i, class = %i, type = %i, parent slot = %i", baginst->GetID(), baginst->GetItem()->ItemClass, baginst->GetItem()->ItemType, Inventory::CalcSlotId(slot_id));
+		}
+		else {
+			LogFile->write(EQEMuLog::Error, "Inventory::_PutItem: Parent Bag instance is NULL at parent slot %i", Inventory::CalcSlotId(slot_id));
+		}
+		
 		if (baginst && baginst->IsType(ItemClassContainer)) {
 			baginst->_PutItem(Inventory::CalcBagIdx(slot_id), inst);
 			result = slot_id;

This will tell us what's going on with the bag instance that might cause that con check to fail.