The issue seems to be this:
 
 
2013-02-19 21:15:33 - main  - Create a backup of C:\Games\Piranha Games\MechWarrior Online\Bin32\CryRenderD3D11.dll
2013-02-19 21:15:33 - main  - Replacing base file C:\Games\Piranha Games\MechWarrior Online\Bin32\CryRenderD3D11.dll
2013-02-19 21:15:34 - main  - Failed swapping files!!!
2013-02-19 21:15:34 - main  - Exception: The process cannot access the file 'C:\Games\Piranha Games\MechWarrior Online\Bin32\CryRenderD3D11.dll__new' because it is being used by another process.
2013-02-19 21:15:34 - main  - Caught exception in completePatch(): The process cannot access the file 'C:\Games\Piranha Games\MechWarrior Online\Bin32\CryRenderD3D11.dll__new' because it is being used by another process.
2013-02-19 21:15:34 - main  - Caught an exception somewhere in the patcher.  Closing down...
2013-02-19 21:15:34 - main  - Exception messages:
2013-02-19 21:15:34 - main  - The process cannot access the file 'C:\Games\Piranha Games\MechWarrior Online\Bin32\CryRenderD3D11.dll__new' because it is being used by another process.
It can be different files (had it report on the main executable as well), but the patcher crashes there.