GSA suddenly closing with error relying to SER Engines

Hi there,
since yesterday GSA SER is suddenly shutting down after between 10 and 40 minutes of usage.
When I look in the error report windows is showing me, it says this:
Problem signature:
  Problem Event Name:    BEX
  Application Name:    Search_Engine_Ranker.exe
  Application Version:    15.6.6.0
  Application Timestamp:    2a425e19
  Fault Module Name:    SerEngines3.dll
  Fault Module Version:    0.0.0.0
  Fault Module Timestamp:    5f93db29
  Exception Offset:    003de9bc
  Exception Code:    c0000409
  Exception Data:    00000007
  OS Version:    6.3.9600.2.0.0.272.7
  Locale ID:    1033
  Additional Information 1:    8c24
  Additional Information 2:    8c244decc99d82288c58308af312cb48
  Additional Information 3:    e476
  Additional Information 4:    e47613786e5101df743dbd770a16bef1

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Has anyone an idea what I may do? Thanks in advance