ctb & stb are the extensions used for pen tables in plotting without including those (presuming you are using plot styles at all) it's difficult for the recipient to guess what a line is supposed to look like on paper. (Is blue supposed to plot out fat, thin, medium?)
standard fonts would be those installed either with an basic Windows setup, or a plain stock AutoCAD install. If you've added & are using non-standard fonts, the the recipient's version will substitute fonts to display text using something they have instead of something they don't have.
for maximum portability between organizations, it's safest to stick with RomanS as an shx 'stroked' font, and Arial or Calibri as the TTF font. If your drawing uses anything else, it may be a non-standard.
You can lok at the font files being used by running the STYLE command and picking through the named styles to see what's required. Or you can use the -STYLE (with a hyphen in front, to get a screen listing all of the style in use with their fonts. that output will look like:
Command: -style
Enter name of text style or [?] <Arial>: ?
Enter text style(s) to list <*>:
Text styles:
Style name: "Arial" Font typeface: Arial
Height: 0'-0" Width factor: 1.0000 Obliquing angle: 0.0000
Generation: Normal
Style name: "Legend" Font typeface: Calibri
Height: 0'-0" Width factor: 1.0000 Obliquing angle: 0.0000
Generation: Normal
Style name: "romans" Font files: romans.shx
Height: 0'-0" Width factor: 0.9000 Obliquing angle: 0.0000
Generation: Normal
Also - check the linetypes in use -- and see if any use complex characters that may require a shape file to create them. If they do, and you don't supply it the recipient will get an alert about a missing shx file.
![Autodesk Design & Make Report](https://forums.autodesk.com/t5/image/serverpage/image-id/1350519iCB55845EBFC43016/image-size/large?v=v2&px=999" "Autodesk Design & Make Report")
