Error Can't use string ("0") as an ARRAY ref while "strict refs"

Hello,

I am trying to display responses based on a single select grid question S5c.
The grid question has 3 columns.
(It could have up to 75 rows depending on what they choose in a previous question)

In the next question, I want to add the option(s) chosen in the grid.

I am attaching my perl code below, when I reach the question I encounter a script error with the above error message. Could you help please?

[% Begin Unverified Perl
my $i=1;

for ($i=1; $i<=75; $i++)
{
if (VALUE("S5c_r".$i)==1 || VALUE("S5c_r".$i)==2 || VALUE("S5c_r".$i)==3 )

{
ADD("S5aList",$i);
}
}
End Unverified %]