If you want to push a ref onto a shared array, you have to share that ref first:

#!/usr/bin/perl

use strict;
use threads;
use threads::shared;
use tmp;

my $rf = tmp->new();

share(my @data);

my @threads;
for ( my $count = 1; $count <= 10; $count++) {
        my $t = threads->new(\&sub1, $count);
        push(@threads,$t);
}
foreach (@threads) {
        my $num = $_->join;
        print "done with $num -- @data\n";
}
print "End of main program  @data\n";

sub sub1 {
        my $num = shift;
        print "started thread $num\n";
        print "done with thread $num\n";
        push (@data,share( $rf )); #### NOTE CHANGE HERE!
        return $num;
}
[download]

With that change, your code runs:

c:\test>807599.pl
started thread 1
done with thread 1
started thread 2
done with thread 2
started thread 3
done with thread 3
started thread 4
done with thread 4
started thread 5
done with thread 5
started thread 6
done with thread 6
started thread 7
done with thread 7
started thread 8
done with thread 8
started thread 9
done with thread 9
started thread 10
done with 1 -- tmp=HASH(0xf4a08) tmp=HASH(0xf4a50) t
done with thread 10
done with 2 -- tmp=HASH(0xf4a98) tmp=HASH(0xf4978) t
done with 3 -- tmp=HASH(0xf4990) tmp=HASH(0xf4b40) t
done with 4 -- tmp=HASH(0xf4b70) tmp=HASH(0xf4ba0) t
done with 5 -- tmp=HASH(0xf4bb8) tmp=HASH(0xf4a68) t
done with 6 -- tmp=HASH(0xf49d8) tmp=HASH(0xf4ae0) t
done with 7 -- tmp=HASH(0xf4c18) tmp=HASH(0xf4b58) t
done with 8 -- tmp=HASH(0xf49f0) tmp=HASH(0xf4a50) t
done with 9 -- tmp=HASH(0xf4c48) tmp=HASH(0xf4978) t
done with 10 -- tmp=HASH(0xf4c60) tmp=HASH(0xf4b40)
End of main program  tmp=HASH(0xf4c78) tmp=HASH(0xf4
[download]

Note: The ability to share blessed references is a relatively new feature of threads::shared. I have done very little with and I am dubious of its benefits, but it does appear to work!