In the "Save As" dialog from the NEdit CNC editor, you could enter a valid Linux filename located on the floppy drive. For example "/cncroot/a/nameofpart.cnc".
In native Linux parlance, there are no "drive letters". Instead, everything is part of one big directory tree. Other drives and devices are "mounted" (attached) to the tree at certain places. On a Centroid system, the floppy disk is automatically mounted to /cncroot/a. Therefore any file name or path that begins with "/cncroot/a/" refers to a file or place on the floppy disk.
Given recent experience, I am reluctant to suggest typing more commands at a Linux command prompt, but....
You could try copying one or more files using the command prompt. This might give you a better chance at finding out what is going wrong.
Press Alt-F6 for a Linux command prompt.
Change directories into your ncfiles subdirectory, by entering the command:
List (display) the names of all the files in that directory by entering the command:
That is "LS", but in lower-case letters. Commands and filenames in Linux are typically in lower case, and are case-sensitive.
Choose one of the files. In this example, I will use your file named "205033.cnc".
Insert a known-good floppy disk that still has some free space on it.
Copy the file over to the floppy disk with the command:
If the command prompt comes back with no error messages displayed, then the copy command succeeded.
If you want to copy every file in the ncfiles directory to the same disk, and you have reason to believe they will fit, you can use the command:
Be careful to include the blank spaces when you type the commands, just as shown in the examples above.
In the last command, for example, there are spaces between "cp", "-v", "*", and "/cncroot/a/".
If you leave any spaces out, it will not work. If you add any extra spaces inside a word (e.g. "/cncroot /a /"), it will not work.
If you need to copy a file that contains space characters within its name (e.g. "205034face.75 rougher.txt"), then when you type the name of that file on the command line, you need to enclose the name in quotation marks.