select PRTG Network Monitor 7.2.5.5114 Setup (Commercial).exe to install the network monitor.
when prtg install complete you need copy the three exe files to the prtg directory which you install file
and you need to another file ArmAccess.dll to directory which you install file.
if you don't copy this file the PRTG Core Server Service can't start normally and raise error: ERRROR 1015
below is error detail on services.msc(EVENT ID 1000:Faulting application name: PRTG Server.exe, version: 7.2.5.5114, time stamp: 0x2a425e19
Faulting module name: unknown, version: 0.0.0.0, time stamp: 0x00000000
Exception code: 0xc0000005
Fault offset: 0x00000000
Faulting process id: 0xcac
Faulting application start time: 0x01cee5bb10e11fb3
Faulting application path: C:\Program Files\PRTG Network Monitor\PRTG Server.exe
Faulting module path: unknown
Report Id: 578711d0-51ae-11e3-b6f1-bc305bc2b85b)