Shell Programming and Scripting

i have a script in bourne called cdrsnokia.sh and inside of it calls a script called resta_dias where it calls the datecalc script (perderabos date calculator).
The purpose is to rest (-) one day arithmetical operation the content of each line and the result is passed to another file lista2;after that, i have to make a report how many lines there are per line ie:

day number
01 4
02 2

lista1 has this structure:
lista1
02/01/2007
02/01/2007
02/01/2007
02/01/2007
03/01/2007
04/01/2007
04/01/2007
05/01/2007
05/01/2007

output should be:
lista2
01/01/2007
01/01/2007
01/01/2007
0/01/2007
02/01/2007
03/01/2007
03/01/2007
04/01/2007
04/01/2007

The real problem is that the script generates the file lista2, in base of this file i couild use grep to count the lines per day, but the the lines in lista2 are in blank.
$more lista2
//
//
//
//
//
//
//
//

As you can see above ths script datecalc is runnind but the values of the fields are in blank.

I was using a former script qith awk, it was working but its too sloowly.

I would apreciate hugly your help.
my work experience is in bourne but no korn shell.

Here i attach the scripts. (i dont attach the datecalc perderabos calculator)

cdrsnokia.sh
ajusta_fecha()
{
cut -f1 -d " " listacdrs|sort -t/ -k2 > lista1
valida=`cut -f2 -d "/" lista1|uniq|grep -v $mes lista1|uniq`
if [ $? -eq 0 ]
then
resta_dias
else
}

resta_dias
#!/bin/ksh
#typeset -Z2 month2 day2
while IFS="/" read day month year; do
set +A a $(datecalc -a $year $month $day -1)
day2=${a[2]}
month2=${a[1]}
echo ${day2}/${month2}/${a[0]}
done < lista1 > lista2
exit 0

This line is wrong:
set +A a $(datecalc -a $year $month $day -1)
You need a space between the minus sign and the 1... like this:
set +A a $(datecalc -a $year $month $day - 1)