I have had so many issues on how to download, extract and install this software on SCO. And I'm sure there are loads of people having or had the same issue as I am having.
So the question is, how do I install software in SCO?
I have found this on the SCO FTP site, I hope this helps other people as it did help me.
To unzip the TAR folder: tar xvf osr507mp5_vol.tar
To Install the Maintenance Pack: You will need to go to the SCOADMIN (login as root) and Install media. Type /usr/spool/patches/osr507mp5 in the path.
All is explained in the Documentation in that link I added.