error verifying data in ram

[testlog]

Hi,
I run burn-in test (CPU,RAM,Video,HDD) for my 512MB 400MHZ, and i get error for RAM test.
below us the log. Could somebody explain to me these two lines?
Virtual Offset: 286A49A4 Read: 0 Expected 243
Virtual Offset: 31D56864 Read: 0 Expected 85

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DETAILED EVENT LOG
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LOG NOTE: 2008-04-24 10:47:34, Status, Main Tests started
LOG NOTE: 2008-04-24 10:47:35, Video, Video test starting: Duty cycle = 90. Test on primary monitor (0). (x,y) = (310,400). WxH = 300x200.
SERIOUS : 2008-04-26 20:41:45, RAM, Error verifying data in RAM
LOG NOTE: 2008-04-26 20:41:45, RAM, Virtual Offset: 286A49A4 Read: 0 Expected 243
SERIOUS : 2008-04-27 18:19:12, RAM, Error verifying data in RAM
LOG NOTE: 2008-04-27 18:19:12, RAM, Virtual Offset: 31D56864 Read: 0 Expected 85
LOG NOTE: 2008-04-28 09:05:57, Status, Test run stopped

[David (PassMark)]

Looks like the RAM is bad (or the bus that connects the RAM to the CPU).

Could somebody explain to me these two lines?
Virtual Offset: 286A49A4 Read: 0 Expected 243

At RAM location 286A49A4 the value of 0 was read from the RAM. But the value of 243 was previously stored in that location. If your memory doesn't remember the values you store in it, then this is a serious problem.

[testlog]

did the burnin test scan all the ram address?
why the error happend after about 2 days of testing.
I have test different configuration of RAM, and i just stop it after 24hrs test.
what does your recommendation for the testing hours?