OK, you need to search directory A recursively until you find the first sub-directory named org.apache.ant.x.y (where x and y are integers). The module File::Find::Rule is useful for this.

I created a directory structure like this:

862_SoPW
|-- weblogic_5
    |-- A
        |-- B
            |-- org.apache.ant.1.3
                |-- bin
|-- weblogic_6
    |-- A
        |-- B
            |-- C
                |-- org.apache.ant.1.4
                    |-- bin
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and ran the following script from directory 862_SoPW:

#! perl
use strict;
use warnings;
use File::Find::Rule;

for (5 .. 7)
{
    my $ant_home = get_ant_home('weblogic_' . $_) // 'not found';
    print "In weblogic_$_, ant home is: $ant_home\n";
}

sub get_ant_home
{
    my $test_dir   = shift;
    my $module_dir = $test_dir . '/A';
    my @subdirs    = File::Find::Rule->directory->in($module_dir);

    for (@subdirs)
    {
        return $_ if /org\.apache\.ant\.\d+\.\d+$/;
    }
}
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Output:

 1:45 >perl 862_SoPW.pl
In weblogic_5, ant home is: weblogic_5/A/B/org.apache.ant.1.3
In weblogic_6, ant home is: weblogic_6/A/B/C/org.apache.ant.1.4
In weblogic_7, ant home is: not found

 1:46 >
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I think you should be able to adapt this to your requirements.

Hope that helps,