First your $key is invalid for Crypt::Rijndael

wrong key length: key must be 128, 192 or 256 bits long at ./928418.pl line 8

# keys must be 128, 192 or 256 "bits" long, 

# 8 bits in a letter, so 8 x 16 = 128
#my $key = 'abcdefgghjkloiuy'; #128 bits or 8 x 16
my $key = 'abcdefgghjkloiuyabcdefgghjkloiuy'; #256 bits or 8 x 32
print "key->$key\n";
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Second, you didn't use warnings; and use strict; so $ndid is undefined

What do you want us to do with broken and incomplete code?