... libclntsh.so.10.1: cannot open shared object file ...

Try setting LD_LIBRARY_PATH before starting the script. Or re-exec the program — something like this (at the beginning of the script):

BEGIN {
    my $prahome = "/u01/oracle/product/10.2.0/client_1";
    my $oralib  = "$orahome/lib";
    unless ($ENV{LD_LIBRARY_PATH} =~ /\Q$oralib/) {  # avoid endless l
+oop
        $ENV{ORACLE_HOME}     = $orahome;
        $ENV{LD_LIBRARY_PATH} = $oralib;
        $ENV{PATH} = "/bin:/usr/bin:$orahome/bin:/home/appowner/bin:."
+; 
        exec $0, @ARGV;
    }
}
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Some OSes / dynamic loaders cache the lib search paths upon exec, so setting them after starting the process has no effect.