Post date: Jun 17, 2020 8:32:46 PM
As of today, Squad Leader Module version 4.2.2 does not work with Vassal 3.3.0. I recommend using VASSAL version 3.2.17 until this is resolved.
To downgrade to Vassal version 3.2.17 just reinstall from the release archive.
Alternately, multiple versions of VASSAL may be installed simultaneously. The Vassal Support group has instructions here.
Of course, you can visit the Vassal Squad Leader page for the current VSQL module 4.2.2.