Newbie, need help with PHP

Hello,
I have downloaded QuickPDFLibrary QuickPDFAX0814 and tried to split a pdf like in the Developers guide.
Problem is. Total Pages shows only 1 instead of 31 pages of the PDF file.
Next is a crash with DocumentRemove:
com->RemoveDocument(1476395008)
Description:</b> List index out of bounds (1)'

    $qp1 = new COM("QuickPDFAX0814.PDFLibrary");
   
    $pdfsource = $file_name;
    $qp1->LoadFromFile($pdfsource,"");
    
    // Use the SelectedDocument function to get the
    // document ID of the file that we just loaded.
    $DocID = $qp1->SelectedDocument();
    // Count the total number of pages in the
    // selected document. We need the total
    // number of pages before we can use the
    // ExtractFilePages function.
    $TotalPages = $qp1->PageCount();
   
    echo "total pages ist $TotalPages <br>";
   
    // Remove the selected document from memory.
   
    $qp1->RemoveDocument($DocID);
   
    //QP.RemoveDocument(DocID);
    // Loop through each page in the document
    // and use the ExtractFilePages function
    // to copy and save each page in the
    // document to a new document.
    for ( $n = 1; $n < $TotalPages; $n++)
    {
        echo "schleife $n <br>";
        $qp1->ExtractFilePages($pdfsource, "sample_split_" + Convert.ToString(n) + ".pdf", Convert.ToString(n));
    }

Can anybody helpme or give me some exampes?

kind regards
Hans