This behaviour is observed on co-located setups, wherein NNMi v2019.05 is already deployed and using HPOvPerlA-5.26.006-1.x86_64.
The higher version of Perl being used by NNMi conflicts with the install of NPS v2018.11 which is still using Perl v5.16
A hotfix is available to resolve this issue and the same should be deployed prior to the installation of iSPI Performance for Metrics v2018.11
For Windows : Colocated_Win_NPS_2018.11_HF.tar.gz
For Linux : Colocated_Lin_NPS_2018.11_HF.tar.gz