CC @josephsl

Confirmed. Using NVDA master-14274,18073792 (temporary copy) on a Windows 8.1 system, I was alarmed when I was able to successfully and consistently replicate these errors consecutively because the error sounds were quite frightening. :) Assuming you have more than one keyboard layout to toggle between (I have three; Hindi Traditional, English India and English US), follow the below steps to replicate the described error.
STR

• Wherever in Windows your focus is, press Windows+Spacebar.
• If NVDA does not play the error sound at this first go itself, press Windows+Space again until you do hear the error sound being played. In my limited testing, NVDA never takes more than three presses of Windows+Space to play the error sound.
• Once you hear the error sound once, press the read current line command (NVDA+L in my laptop) again and again to be greeted by a constant series of error sounds.
  I am unsure if the error produced by Windows+Space is different from that produced by a subsequent NVDA+L, so I'll post each of them below respectively:

Windows+Space Error
Input: kb(laptop):windows+space
ERROR - eventHandler.executeEvent (15:44:45.739):
error executing event: focusEntered on <NVDAObjects.UIA.UIA object at 0x048C7EF0> with extra args of {}
Traceback (most recent call last):
File "eventHandler.pyc", line 143, in executeEvent
File "eventHandler.pyc", line 91, in init
File "eventHandler.pyc", line 98, in next
File "NVDAObjects_init_.pyc", line 929, in event_focusEntered
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects_init.pyc", line 808, in _get_isPresentableFocusAncestor
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects\UIA_init.pyc", line 1056, in _get_presentationType
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects_init.pyc", line 624, in _get_presentationType
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects\UIA_init.pyc", line 996, in get_states
File "NVDAObjects\UIA_init.pyc", line 684, in prefetchUIACacheForPropertyIDs
COMError: (-2147024809, 'The parameter is incorrect.', (None, None, None, 0, None))
ERROR - eventHandler.executeEvent (15:44:45.770):
error executing event: focusEntered on <NVDAObjects.UIA.UIA object at 0x048C7830> with extra args of {}
Traceback (most recent call last):
File "eventHandler.pyc", line 143, in executeEvent
File "eventHandler.pyc", line 91, in init
File "eventHandler.pyc", line 98, in next
File "NVDAObjects_init.pyc", line 929, in event_focusEntered
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects_init.pyc", line 808, in _get_isPresentableFocusAncestor
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects\UIA_init.pyc", line 1056, in get_presentationType
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects_init.pyc", line 624, in get_presentationType
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects\UIA_init.pyc", line 996, in get_states
File "NVDAObjects\UIA_init.pyc", line 684, in prefetchUIACacheForPropertyIDs
COMError: (-2147024809, 'The parameter is incorrect.', (None, None, None, 0, None))
ERROR - eventHandler.executeEvent (15:44:45.802):
error executing event: gainFocus on <NVDAObjects.UIA.UIA object at 0x045E9130> with extra args of {}
Traceback (most recent call last):
File "eventHandler.pyc", line 143, in executeEvent
File "eventHandler.pyc", line 91, in init
File "eventHandler.pyc", line 98, in next
File "C:\Users\DELL-PC\AppData\Roaming\nvda\addons\remote\globalPlugins\remoteClient_init.py", line 341, in event_gainFocus
File "eventHandler.pyc", line 98, in next
File "appModules\explorer.pyc", line 280, in event_gainFocus
File "eventHandler.pyc", line 98, in next
File "NVDAObjects_init.pyc", line 936, in event_gainFocus
File "NVDAObjects_init.pyc", line 831, in reportFocus
File "speech.pyc", line 376, in speakObject
File "speech.pyc", line 270, in speakObjectProperties
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects\UIA_init.pyc", line 1233, in get_value
File "NVDAObjects\UIA_init.pyc", line 667, in _getUIACacheablePropertyValue
COMError: (-2147024809, 'The parameter is incorrect.', (None, None, None, 0, None))

NVDA+L Error
Input: kb(laptop):NVDA+l
ERROR - scriptHandler.executeScript (15:53:13.573):
error executing script: <bound method GlobalCommands.script_reportCurrentLine of <globalCommands.GlobalCommands object at 0x046A1230>> with gesture u'NVDA+l'
Traceback (most recent call last):
File "scriptHandler.pyc", line 187, in executeScript
File "globalCommands.pyc", line 142, in script_reportCurrentLine
File "textInfos\offsets.pyc", line 348, in expand
File "textInfos\offsets.pyc", line 330, in _getUnitOffsets
File "textInfos\offsets.pyc", line 249, in getLineOffsets
File "NVDAObjects_init.pyc", line 41, in _getStoryText
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects_init.pyc", line 996, in _get_basicText
File "baseObject.pyc", line 34, in get
File "baseObject.pyc", line 110, in getPropertyViaCache
File "NVDAObjects\UIA_init.pyc", line 1233, in get_value
File "NVDAObjects\UIA_init.pyc", line 667, in _getUIACacheablePropertyValue
COMError: (-2147024809, 'The parameter is incorrect.', (None, None, None, 0, None))

Please let me know if any further diagnostic information is required for troubleshooting purposes.

@bhavyashah is this still reproducible on Windows 8.1?

No updates since almost three years, I cannot reproduce this with las alpha of NVDA. Closing as abandoned and works for me. Please comment on this if you are still seeing this issue and we can reopen it. Thanks.