If the download was corrupted sbopkg should have warned you when checking the md5sum, but removing /var/cache/sbopkg/mlt-0.8.2.tar.gz and trying a rebuild won't hurt.
I can confirm that the PAL files are there.
They are generated by a luma binary built in /tmp/SBo/mlt-0.8.2/src/modules/lumas and convert from imagemagick is used in the process too.
Can it be you are not using a Slackware full installation?
Remember that only full installs of the latest stable Slackware are supported if you want to run SBo scripts