Error: Invalid Input on my program

[StephenG1CMZ]

I think that one problem may be that the INPUT syntax has changed since Han wrote that in 2013.

Briefly, where previously one would have
INPUT... varname,
now one should use
IINPUT...{{varname,[numbers]}}
Where numbers specifies the type of input, for example
INPUT...{{varname,[3]}} might specify string, or 6 might specify list, or 3,6 would be either.
The number you want is probably (DOM_STRING-1).

Check the INPUT help for the exact syntax.

(But if you are using CAS input, I don't know).