Problems transferring Twin Express to Amiga A500

[Ilwrath]

When I try this, I get the Message: Not a DOS Disk.

That is meaning that it's not an AmigaDOS disk -- which is correct -- you're trying to read a PC disk.  What you need to do is mount the PC0: device on your Workbench 2.1 "Storage" disk.  Then you can read PC disks by using the name PC0: instead of DF0:

P.S. I have had a look at my RAM disk on Work Bench, and it says it's full! The three folders that are on: ENV, Clipboards and T? Should I delete these?

RAM disk is always shown as 100% full.  It uses free system memory to inflate to whatever size is needed.  So, despite it being 100% full, you can still copy more stuff to it, so long as you have free memory in the computer (free RAM count is at the top of the workbench screen)

[Ilwrath]

100% full bug in workbench

I wouldn't really call it a bug...  Since the RAM disk is only as large as its contents, its always 100% full.  The gauge is totally accurate, yet, in this case, 100% useless.  ;-)

[Ilwrath]

Damn it! I was so close to getting it sorted! I mounted the PC0: device and tried to read the disk, the only problem was that I was still typing DF0: so this was causing the same problem.

Yep.  I remember doing the same thing when learning how to use CrossDOS.  :-)  Took me a while to figure out that the same drive had different abilities by calling it different names.  ;-)

If I manage to get the Amiga to read the disk with Twin Express on it, how do I install the program to the ramdisk?

Well, that depends.  You probably don't need to "install" it, per se.  If it's just an executable, it should run from anywhere.  

If it's a .lha file, you'll have to uncompress it, and copy the files to their proper locations on your (copy of -- not the original! -- always use backups!) Workbench disk.  

I was told it would have to be coverted to a ADZ file, because the ADF file is to big to fit on a 720KB disk, is this true?

AFAIK, an ADZ is just a zipped ADF file.  And you are correct that a standard ADF of an 880KB disk won't fit on a PC 720KB disk.