Invalid access to memory

Hi,
The laptop was on sleep mode. the target machine was shutdown. When I opened the laptop this morning, WinSCP popped the regular message that it cannot access the target machine. After clicking OK, this error appeared. This is a first time I think.

WinSCP 6.3.5

Error message:
Invalid access to memory.

Stack trace:
(0043A85B)
(00098F2F) ntdll.dll
(000781B1) ntdll.dll.KiUserExceptionDispatcher
(00492FBD)
(00492FBD)
(0049304C)
(004A58F2)
(00492CDD)
(003DFB03)
(00226F2C)
(00032431) USER32.dll
(00023231) USER32.dll
(00021AE0) USER32.dll
(0002162B) USER32.dll.DispatchMessageW

Status: unknown_rel_addr

The problem happens rarely. I cannot reproduce it.