[cem] Problems installing cem

Hi everyone, I have problems in running cem which I believe is related to an error in the installation procedure. I installed cem using: sysdir set PLUS "U:[folder location]ado\plus" ssc install cem When running cem i get the error message: file U:[folder location]ado\plus/c/cem-mata.do not found (error occurred while loading cem.ado) But I checked: the file "cem-mata.do" is exactly at the location where Stata is looking for it. Folder and file are named correctly and I can open it. Everything seems fine with the file. I have no idea how to fix this. Any help? Thank you, Anika