worked in 2.5.1 not in 2.7.2

[Robert Mann]

I just upgraded to the 2.7.2 but I wrote this in 2.5.1 and it was working?

not sure what this script error is telling me?

Type	Operators *: error in right operand
Object	Calc Spring Rate
Line	put tfr_mx_multiplier * fld "weight" + tfr_mx_additive into fld
"fr_mx_rate"
Hint	button id 1150 of card id 1002 of stack "K:/hypercard/data files/Spring
Calc.rev"

here is the script

on mouseUp
  if fld "weight" is empty then
    answer error "Please enter a weight."
    exit mouseUp
  end if

  put word 1 of fld "Select springcalc" into tfr_mx_multiplier
  put word 2 of fld "Select springcalc" into tfr_mx_additive
  put tfr_mx_multiplier * fld "weight" + tfr_mx_additive into fld
"fr_mx_rate"
end mouseUp

Robert Mann