print Dumper ( $xst->{cmts}{STBDSG}{dsg} );
print Dumper ( $xst->{cmts}{STBDSG}{dsg}[0] );
print Dumper ( $xst->{cmts}{STBDSG}{dsg}[0]{tag1} );
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$VAR1 = [
          {}
        ];
$VAR1 = {};
$VAR1 = undef;
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my $xst;        

if((not defined $xml) or ($xml =~ m/read\stimeout/i)){
    &printXMLErr('request timed out');
} else {
    my $xs = XML::Simple->new();
    $xst = eval { $xs->XMLin($xml,KeyAttr=>1) };
    &printXMLErr($@) if($@);
}
[download]

Try working back up the tree one step at a time to see what's happening:

print Dumper ( $xst->{cmts}{STBDSG} );

then

print Dumper ( $xst->{cmts} );
[download]

Can you put some sample files up somewhere else - e.g. Dropbox - I could then have a look.

Sorry tangent, but I don't have an option for it. The other part of code where fetching data is working as expected is where xml was like:

<cmts>
    <name field_name="Name">cts01nsocmo</name>
    <object field_name="Nemos Object">888</object>
    <vendor field_name="Vendor">xyz</vendor>
</cmts>
[download]

Which was converted as:

$VAR1 = {
  'cmts' => {
    'name' => {
                'content' => 'cts01nsocmo',
                'field_name' => 'Name'
              },
    'object' => {
                  'content' => '888',
                  'field_name' => 'Nemos Object'
                },
    'vendor' => {
                  'content' => 'xyz',
                  'field_name' => 'Vendor'
                }
[download]

So basically no array and 'content' was there. Where it is not working, xml is like:

<cmts>
  <STBDSG>
      <dsg>
        <tag1>1</tag1>
        <tag2>caSystemId</tag2>
      </dsg>
      <dsg>
        <tag1>2</tag1>
        <tag2>gaSystemId</tag2>
      </dsg>
    </STBDSG>
</cmts>
[download]

Which was converted as:

'cmts' => {
        'STBDSG' => {
            'dsg' => [
                     {
                       'tag1' => '1',
                       'tag2' => 'caSystemId',
                     },
                     {
                       'tag1' => '2',
                       'tag2' => 'gaSystemId',
                     }
                     ]
                 },
[download]

Update: It seems that answer to why $xst->{cmts}{STBDSG}{dsg}[0]{tag1} is getting undef is known to either KeyAttr or forcearray (or both). I am trying to find it out from them :-)