As per Microsoft: "The buffer that stores keystrokes when you enter data faster than the application can process it filled up before you stopped typing. Some of the keystrokes were lost". See MSW2KDB
for additional information about this event.
To increase the keyboard buffer size, run Regedit and go to:
Look for (or create if not present) the "KeyboardDataQueueSize" DWORD [REG_DWORD] Value in the right hand pane -> double-click on it -> check the Decimal box -> double the value shown there (default is 100) -> type in the new integer number -> click OK. Then, under the same Registry key, find/create the "PollStatusIterations" DWORD Value, and increase it from 1 (default) to 2 or 4, by performing same steps above, until your keyboard no longer exhibits interruptions.