Maybe this?
Code:
@echo off & setLocal enableDELAYedeXpansioN
:main
for /f "tokens=* delims= " %%a in ('dir/b *.htmlz') do (
copy "%%~fa" "%%~da%%~pa%%~na.zip"
"C:\Program Files (x86)\ubook\uBook.exe" "%%~da%%~pa%%~na.zip"
)
Pause
I might have gone slightly overboard in there

The %~da returns the drive letter (ends with a : )
The %~pa returns the path only (fully pathed, and ends with a \ )
The %~na returns just the file name