If ( QP.EncryptionStatus > 0 ) Then

     QP.Decrypt;

Here's a sample from Wilbur:

http://www.quickpdf.org/forum/problem-with-mergefilelistfast-in-delphi_topic3309_post13174.html?KW=MergeFileListFast#13174

Here's another sample:

http://www.quickpdf.org/forum/how-to-use-this-function_topic2087.html

Something relevant from the kb:

http://www.debenu.com/kb/merge-pdf-files-together-programmatically/

On page 28/29 of the developer guide you'll find a working sample, too.

But first you should clean and restructure your code ;-)

procedure TMainForm.Merge1Click(Sender: TObject);

var

done : boolean;

fn1, fn2, ftmp, savename, listname :string;

zz, i, ures : Integer;

dqpl : TDebenuPDFLibrary1212;

begin

savedlg.Title := 'Enter Your Save File Name';

savedlg.Execute;

savename := savedlg.FileName;

if savename = '' then exit;

if pos('.PDF',Uppercase(savename)) = 0 then

   savename := savename +'.PDF';

// open file - get first file

opendlg.Title := 'Select your initial PDF file to merge ';

opendlg.execute;

fn1 := opendlg.FileName;

if fn1='' then exit;

listname:= 'mergeList';

dqpl := TDebenuPDFLibrary1212.Create();

ures:= dqpl.UnlockKey('key here');

if ures = 1 then begin

    DQPL.ClearFileList(listname);

    DQPL.AddToFileList(listname,fn1);

    done := false;

    // loop

    opendlg.Title := 'Select the PDF file to append ';

    while not done  do begin

        // open file get next

        opendlg.FileName :='';

        opendlg.Execute;

        opendlg.Title := 'Select the PDF next file to append ';

        fn2:= opendlg.FileName;

        DQPL.AddToFileList(listname,fn2);

        // continue/done

        if MessageDlg( 'Done?' ,mtconfirmation,[mbYes,mbNo],0) = mrYes then Done := true;

    end;

    DQPL.MergeFileListFast(listname,savename);

    dqpl.free;

end;

end;