🚀 go-pugleaf

I am trying to install the MSH device handler -- 

I'm getting a "Reserved not assigned" message when I type "mount
msh:", and MSH does not appear to have been mounted at all, though
I've copied the messydisk.device file to my devs: directory, and the
MessyFileSystem file to my L: directory.

I have an Amiga 500 with the A501 512K memory board and an A1010 (I
think) external floppy drive, and I'm running AmigaDOS 1.3 on 1.2
ROMS.  Could this have something to do with my problem?.  

Here is the relevant part of my mountlist file.  I would appreciate
any help indeed!  Thank you!

----mountlist contents----
/* Messy file system on messy blocks: */
MSH:	FileSystem = l:MessyFileSystem
	Device = devs:messydisk.device
	Unit = 1
	Flags = 0
	LowCyl = 0 ; HighCyl = 79
	Surfaces = 2
	BlocksPerTrack = 9
	Buffers = 5
	BufMemType = 1	/* messydisk needs no chip mem */
	BootPri = 0
	Stacksize = 4096
	Priority = 5
	GlobVec  = -1
#
MS2:	FileSystem = l:MessyFileSystem
	Device = devs:messydisk.device
	Unit = 2
	Flags = 0
	LowCyl = 0 ; HighCyl = 79
	Surfaces = 2
	BlocksPerTrack = 9
	Buffers = 5
	BufMemType = 1	/* messydisk needs no chip mem */
	BootPri = 0
	Stacksize = 4096
	Priority = 5
	GlobVec  = -1
#
/* Amiga Old filing system on messy blocks: */
MF1:	Device = devs:messydisk.device
	Unit = 1
	Flags = 0
	Priority = 4
	LowCyl = 0 ; HighCyl = 79
	Reserved = 2
	Surfaces = 2
	BlocksPerTrack = 9
	Buffers = 5
	BufMemType = 1
	BootPri = 0
#
/* Messy file system on Amiga blocks: */
DS1:	FileSystem = l:MessyFileSystem
	Device = devs:trackdisk.device
	Unit = 1
	Flags = 0
	LowCyl = 0 ; HighCyl = 79
	Surfaces = 2
	BlocksPerTrack = 11
	Buffers = 5
	BufMemType = 3	/* trackdisk needs CHIP mem */
	BootPri = 0
	Stacksize = 4096
	Priority = 5
	GlobVec  = -1

--
T. Kim Nguyen 				  kim@watnow.waterloo.{edu|cdn}
"The last thing I need is a f***ing 		kim@watnow.uwaterloo.ca
 conscience!..." 	    {uunet|utzoo|utai|decvax}watmath!watnow!kim
Systems Design Engineering  --  University of Waterloo, Ontario, Canada