*.deb files will not install

[arkansas-coder]

I am trying to install the two *.deb files but am getting errors. For example, the argon1 errors are:

openhab@openHAB-4:~/argon1$ sudo apt install ./argon1_0.2.1_all.deb
Reading package lists... Error!
E: Sub-process Popen returned an error code (2)
E: Encountered a section with no Package: header
E: Problem with MergeList /home/openhab/argon1/argon1_0.2.1_all.deb
E: The package lists or status file could not be parsed or opened.

Similar errors occur when using dpkg. Am I doing something wrong, or ...?