so how does the create unit chetas work.

[Roy1991]

You forgot the quotation marks.

For example, to create 4 units of roman ballistas in Mediolanium, with 4 experience, gold weapons & armour, you have to type:

create_unit "Mediolanium" "roman ballista" 4 4 3 3

Then, use this dictionary name (with the _ characters) and see if that does the trick.

The cheat doesn't work if you use the dictionary name, you just have to use the unit type (the line right above the dictionary name)