Hi Corion - Sorry for confusing you, Here is my complete function GetMappletList() i am trying to call,but i am calling it from same script in which the function was declared, The variable $SourceTableName used in the if condition is using values from global variable declared in the script.I am trying to copy portion of xml elements from the source file $MappletXmlName to another file $OutFileName which too have some elements.

sub GetMappletList
   {
        my ($TableNm,$ColumnNm,$DomainNm,$AlgoNm);
        my @MaskingAlgorithmList;
        my @MappletNode;
       my $MpltRefFile_Dir = shift;
       my $MappletXmlName;
       open GET_MAPPLET_LIST, "<","$Profiler_Dir/$MpltRefFile_Dir/Inve
+ntory.rpt" or die "ERROR : Couldn't Open $Profiler_Dir/$MpltRefFile_D
+ir/Inventory.rpt $!";
       while (my $InvtoryCol = <GET_MAPPLET_LIST> )
              {
                       chomp $InvtoryCol;
                      ($TableNm,$ColumnNm,$DomainNm,$AlgoNm) = split(/
+,/,$InvtoryCol);
                      if ($TableNm =~ /$SourceTableName/)
                           {
                             
                              $MappletXmlName = "$Mapplet_Dir/$AlgoNm.
+XML";
                              my $MpltParser = XML::LibXML->new();
                              my $MpltXml = $MpltParser->parse_file("$
+MappletXmlName");
                              my $TargetXml = $MpltParser->parse_file(
+"$OutFileName");
                              my @MappletNode = $MpltXml->findnodes('/
+POWERMART/REPOSITORY/FOLDER/MAPPLET');
                              
                              

                              for my $node (@MappletNode) 
                                     {


                                               $TargetXml->appendChild
+($node);
                                               #print $node->toString(
+2);
                                               
                                       }

                           }
              }
       close(GET_MAPPLET_LIST);
   
   }
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Again, what steps have you done to ensure that the file you give to ->parse_file exists and contains valid XML?

Maybe it helps to print out $MappletXmlName and $OutFileName. Also, $AlgoNm seems to play a part in constructing the filename.

Here is my updated code, i am able to print the exact node and associated sub elements i want to copy but how can i write the content of $node which is also getting printed in the output to the target file

sub GetMappletList
   {
        my $Target_node;
        my ($TableNm,$ColumnNm,$DomainNm,$AlgoNm);
        my @MaskingAlgorithmList;
        my @MappletNode;
       my $MpltRefFile_Dir = shift;
       my $MappletXmlName;
       open GET_MAPPLET_LIST, "<","$Profiler_Dir/$MpltRefFile_Dir/Inve
+ntory.rpt" or die "ERROR : Couldn't Open $Profiler_Dir/$MpltRefFile_D
+ir/Inventory.rpt $!";
       while (my $InvtoryCol = <GET_MAPPLET_LIST> )
              {         
                       chomp $InvtoryCol;
                       
                      ($TableNm,$ColumnNm,$DomainNm,$AlgoNm) = split(/
+,/,$InvtoryCol);
                      if ($TableNm =~ /$SourceTableName/)
                           {
                              print " The Workflow xml nme is $OutFile
+Name\n"; 
                              $MappletXmlName = "$Mapplet_Dir/$AlgoNm.
+XML";
                              print "The Dir name is $MappletXmlName\n
+";
                              my $MpltParser = XML::LibXML->new();
                              my $TargetXml = $MpltParser ->parse_file
+("$OutFileName");
                              my $MpltXml = $MpltParser->parse_file("$
+MappletXmlName");
                                my @MappletNode = $MpltXml->findnodes(
+'//MAPPLET');
                              
                              for my $node (@MappletNode) 
                                    {


                                               print $node->toString(1
+); 
                                               
                                               
                                               
                                               
                                     }

                           }
              }
       close(GET_MAPPLET_LIST);
   
   }
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The source file content is given below

<?xml version="1.0" encoding="Windows-1252"?>
<!DOCTYPE POWERMART SYSTEM "powrmart.dtd">
<POWERMART CREATION_DATE="01/24/2014 18:27:23" REPOSITORY_VERSION="181
+.90">
<REPOSITORY NAME="xyz" VERSION="181" CODEPAGE="MS1252" DATABASETYPE="O
+racle">
<FOLDER NAME="DM_POC" GROUP="" OWNER="Administrator" SHARED="NOTSHARED
+" DESCRIPTION="" PERMISSIONS="rwx---rwx" UUID="c08574eb-cdf5-4bd1-bda
+0-d08519348c79">
    <MAPPLET DESCRIPTION ="" ISVALID ="YES" NAME ="mplt_Key_Lkp_NID" O
+BJECTVERSION ="1" VERSIONNUMBER ="1">

*****----THERE ARE COUPLE of OTHER SUB ELEMENTS WHICH ARE NOT GIVEN HE
+RE------****
    </MAPPLET>
</FOLDER>
</REPOSITORY>
</POWERMART>
[download]

The Target xml file content looks like the below one

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE POWERMART SYSTEM "powrmart.dtd">

<POWERMART CREATION_DATE="1/25/2014 14:39:55" REPOSITORY_VERSION="181.
+90">
     <REPOSITORY NAME="rep_brcls_punapp830" VERSION="181" CODEPAGE="MS
+1252" DATABASETYPE="Oracle">
          <FOLDER NAME="DM_POC" GROUP="" OWNER="Administrator" SHARED=
+"NOTSHARED" DESCRIPTION="" PERMISSIONS="rwx---rwx" UUID="c08574eb-cdf
+5-4bd1-bda0-d08519348c79">
               <SOURCE BUSINESSNAME="" DATABASETYPE="Flat File" DBDNAM
+E="Flat_File" DESCRIPTION="" NAME="sample" OBJECTVERSION="1" OWNERNAM
+E="" VERSIONNUMBER="1">
                    <FLATFILE CODEPAGE="US-ASCII" CONSECDELIMITERSASON
+E="NO" DELIMITED="YES" DELIMITERS="," ESCAPE_CHARACTER="" KEEPESCAPEC
+HAR="NO" LINESEQUENTIAL="NO" MULTIDELIMITERSASAND="NO" NULLCHARTYPE="
+ASCII" NULL_CHARACTER="*" PADBYTES="1" QUOTE_CHARACTER="NONE" REPEATA
+BLE="NO" ROWDELIMITER="10" SHIFTSENSITIVEDATA="NO" SKIPROWS="0" STRIP
+TRAILINGBLANKS="NO" />

******-----SOMETHING HERE ,THEY ARE NOT GIVEN AS THEY ARE TOO BIG-----
+------*****

</SOURCE>
          </FOLDER>
     </REPOSITORY>
</POWERMART>
[download]

I want to copy everything between the tags <MAPPLET> </MAPPLET> from source xml to target xml file and the copied content should be placed in the target, between <FOLDER> </FOLDER> tags

I am totally lost myself in finding correct solution to make this work, Please advise me how can i fix it?