Gary has just released a 'bug fix' for MARK 4.2. This new build fixes a bug with retrieving models from a MARK file different than the current results browser file.
You can grab the new build from Gary's site, or directly from this site at
http://www.phidot.org/software/mark/download/
As with all new MARK builds, it is recommended that you (i) first uninstall the old version before (ii) installing the new version.