Some malware or you have installed or created a file called "more.com". It I somewhere on your path. You must find and remove it. "more is a built-in function that seems to be missing. Perhaps you are running PS 1 on
XP?
In any case the error indicates a broken installation or either Windows or PowerShell. "more.com" is an old and no longer existing DOS program.
If you are running PS v1 or V2 then you will be using a dummy more.com that should be in the system folder.
dir C:\Windows\system32\more.com
All later versions of PowerShell use an internal function:
\_(ツ)_/