Hey @matan alter ,
can you please post here the exact versions of the MPs you are trying to install?
It would be also very helpfull if you provide the exact error messages you get while trying to install the 2012 MP and also the AIX MP.
Still when it comes to monitoring Linux/UNIX based Systems it is always a good idea to use the latest version:
System Center 2019 Management Pack for UNIX and Linux Operating Systems
https://www.microsoft.com/en-us/download/details.aspx?id=58208
Having this information would help us making more helpful statement.
Thanks and Regards,
Stoyan