Sounds like an error with the cygwin installation.
Can you check if the file is there, where windows searches it (bin subdirectory)?
Can you check manually that the normal cygwin commands in batches do run successful?
2020-01-16_10-35-21:INFO: ERR C:/cygwin/bin/sh: C:cygwinbinchmod.exe: command not found
yes everything is there. Local commands works fine, but from the oem it seems as the "/" disappears on it way. I suspect locale or TZ variables messing up on its way to the cygwin environment on the target.
From experience: I never had any cygwin<->OEM problem due to locale or TZ things and the log also doesn't show something like that.
It could be a right problem, from your log I can see, the call seems to have backslashs in, but the return of the cygwin/bin/sh tells, there is a problem.
Have you installed cygwin as administrator for all users, do you have setup the Windows services for opensh with all needed rights?
Can you ssh on your windows machine from the aix server and run linux commands there (touch a file, make a chmod)?
There is an internal bug already filed and being worked for this issue.
Bug 28034251 : Agent software is wrongly transferred to Windows host
The workaround that can be used for now is the Silent Instillation Method:
EM 12c, EM 13c: How to Install Enterprise Manager Cloud Control Agent in Silent Mode with the agentDeploy.sh Script Using a Response File (Doc ID 1360083.1)
Not suprised about the bug. Ok, thanks I will do the silent workaround.
Thanks for the update!!
Silent installation should work fine.