0x4E: PFN_LIST_CORRUPT is possibly the single strongest error code indicating corrupted memory. I speak from experience having had this error code myself and corrupted memory.
If you have corrupted memory no amount of switching around the RAM sticks will help. It can't be fixed, only replaced. Kingston makes great memory and I would be very suprised if they did not exchange your bad RAM for new RAM free of charge.
Have you ever run Memtest before? It is free, perfectly safe, and the good thing is engages almost immediately after boot-up. This is the address: Memtest86+ - Advanced Memory Diagnostic Tool
(if it doesn't work it is easy to find; if it takes you to any site that requires you to pay -- dont!; this is free). Some advice I give people running the test:
Let it run for a LONG time. The rule is a minimum of 7 Passes; the more Passes after 7 so much the better. There are 8 individual tests per Pass. Many people will start this test before going to bed and check it the next day.
If you have errors you have corrupted memory and it needs to be replaced.
Also, with errors you need to run this test per stick of RAM. Take out one and run the test. Then take that one out and put the other in and run the test. If you start getting errors before 7 Passes you know that stick is corrupted and you don’t need to run the test any further on that stick.