Hmm, could it be that UA in Tools folder is different from the "original"?
I don't remember
Edit:
Just checked, precomp in UA is 0.46, in both 2801 R3 H
Code:
C:\Users\Fee\Desktop\UltraARC 2801 R3 Hotfix\Resources>PComp
Precomp v0.4.6 Windows 32-bit - ALPHA version - USE FOR TESTING ONLY
Free for non-commercial use - Copyright 2006-2017 by Christian Schneider
Usage: precomp [-switches] input_file
And there is only one file missing, namely wrar.exe (for WinRAR archive creation in UA, which no one is using anyway).
Btw:
Did you changed also precomp to 0.46 in Compressor.ini? Since there is a cls for unpacking, but i don't know if this cls will work for any precomp version.
PS:
To use Precomp046 in UA, you have to use MMC compression. Precomp in GUI is only for ZTool/pZLib3