DATA is a file handle, but it looks like your trying to use it as a label.

Also, I'm not sure why your trying to use a matching regular expression. I'd test for equality. Instead of:
next DATA if ($LEV =~ /0/);

try:
next if ($LEV == 0);  # $LEV is a number -- NO DATA
or
next if ($LEV eq '0')  # $LEV is a string -- NO DATA

Without examples of your data, these suggestions are just guesses.

Cheers,

Brent