Time difference summing in mass quantities

I am trying to take a log file from a machine that time-stamps every event that occurs. i can filter out all the nonsense information that's not needed but i need to be able to consistently import data weekly that will calculate differences between timestamps and sum the total, over 6k of line items. but its formatted as such:

2:16:18 error1 occurs on machine
2:16:33 error1 cleared on machine
2:17:05 error2 occurs on machine
2:39:54 error2 clears on machine

this continues for thousands of line items, but i need to be able to calculate the timedifference of when error1 occurs and is cleared, the time difference between when error2 occurs and is cleared and so on and so forth then sum all of it together. is this even possible without having to generate a custom formula and clicking on every cell you want added in to it? any help or ideas would be greatly appreciated.

7-14-2014.xlsx

this is the reduced data on the second worksheet labeled "sheet 1". every time there is a "SetError:" then a "ClearAllErrors(" that time difference must be calculated, and all must be summed together.

i have a way to get the information now, but its tedious, long, and i would like to be able to do this for 7 days a week, x6 the amount of data. hope this helps further. thanks.