open arc.ini
under compression method section find
your_method, change msc_frog to msc_tak , save it and run it again
even then the message appears remove msc _* from the compression method as then there is no way to make it work

Simply there's no need to worry about "Can we have more compression with MSC or other tools here?"
But you can simply use Precomp's Latest version in order to achieve that.
I did repacked it and burned it to my 2DVD5s the size was nearly 6.7Gigs and that was because of my 1.8Ghz Proc and 2Gigs Ram i Used Precomp 3.8A
but still you can achieve nearly 5.5 to 5.9 Gigs Compression cuz it have .biks and .ogg Media files.
Well thats where we get "MSC" usage.
But still it will provide no good i've tried it..
And Yeah Peeps you only need Precomp for this since it have lots of ZLibs Headers in its Files...

thanks