Mine did the same, same model 7155ea1, upgraded with Crucial 1gb ram modules, removed it replaced with the original 512 sticks, booted up fine, then replaced with the 1 gb sticks, everything is fine now, however my cooling fan now stays on all the time, i am stummped, any ideas?
either that or the memory could be bad try trplacing your old on to see if error still occurs if so slot may be bad (you did have it OFF & battery out while installing it assume if not you can fry the slot the ram & the Motherboard)