Hi,
When we speak about currencies/units, first we need to check source and target system in synch with data. once data was same at both sides then you can do the required settings at RSCUR.
if your currencies/units data not in synch with the bw data then try to do transfer global settings from your source system(SRM) to target bw system.
Later try to do the settings, it may works for you.
Thanks