Here's a quick refactoring of the code:

#!/usr/local/bin/perl

use strict;

while (<DATA>) {
    chomp();
    my @rows = split(/\s+/, $_, 7);
    print join ";", @rows , "\n";
}


__DATA__
abc  322 2/3/09 aaa aadda dasdas a1 a2 a3
def  433 3/4/08 dasd bdbdbd wings b1 b2 b3 b4 b5
[download]

Output:
abc;322;2/3/09;aaa;aadda;dasdas;a1 a2 a3;
def;433;3/4/08;dasd;bdbdbd;wings;b1 b2 b3 b4 b5;

I usually like to use a hash table to hold the column names, so here's an example of how I'd handle named columns:

#!/usr/local/bin/perl

use strict;
use Data::Dumper;

# Named column headings
my @columnNames = qw{
    name
    tel
    col3
    col4
    col5
    col6
    notes
};

while (<DATA>) {
    chomp();
    my @rows = split(/\s+/, $_, scalar(@columnNames)); 
    
    my %headings;
    @headings{@columnNames} = @rows;
    print "Dump headings hash: ".Dumper(\%headings)."\n";
}


__DATA__
abc  322 2/3/09 aaa aadda dasdas a1 a2 a3
def  433 3/4/08 dasd bdbdbd wings b1 b2 b3 b4 b5
[download]

Output:
Dump headings hash: $VAR1 = {
          'col5' => 'aadda',
          'col3' => '2/3/09',
          'tel' => '322',
          'notes' => 'a1 a2 a3',
          'name' => 'abc',
          'col4' => 'aaa',
          'col6' => 'dasdas'
        };

Dump headings hash: $VAR1 = {
          'col5' => 'bdbdbd',
          'col3' => '3/4/08',
          'tel' => '433',
          'notes' => 'b1 b2 b3 b4 b5',
          'name' => 'def',
          'col4' => 'dasd',
          'col6' => 'wings'
        };