Problem with checking file existence by using app.openDoc

Question

Hi Folks,
I have to create a script for a big project with many PDF's. (Just like Ingrimm - it's the same company http://forums.adobe.com/thread/747022?tstart=0) This PDF's are made of scanned images. I need to rename the files to names that are extracted from within the file. This is working without problems.
Now there could be the case, that a filename exists already. I don't want the files to be overwritten, so the idea is, that already existing filenames are saved as filename_1, filename_2, etc... (Before I merged them, but this isn't what is wanted.)
For this reason I need to use app.openDoc to check, if a file exists. Yesterday my script worked fine, but after starting it today, I discovered that it started again to overwrite files which are already existing.
I added an app.alert to my catch method to see what error is thrown. The message is: 'NotAllowedError: Security settings prevent access to this property or method.'.
After using google, I found out, that Acrobat is not finding any files. But I checked and there are files which should be doubled.
I have no idea how to fix that problem. Anybody here who can help me?
Regards,
Steffi
* regular expression for search
var idNumber = /08\d\d\d\d\-\d\d\d\-\d\d\d\d\d-\d\d\d/g;
* if possible this function extracts the searched number as string
* @param rematch string which should be searched in document
* @return null if rematch is not found or string if rematch is found
function ExtractFromDocument(reMatch) {
  try {
         var Out = new Object();
         for (var i = 0; i < 1; i++)
          numWords = this.getPageNumWords(i);
          var PageText = "";
          for (var j = 0; j < 30;j++) {
              var word = this.getPageNthWord(i,j,false);
              PageText += word;
          var strMatches = PageText.match(reMatch);
          if (strMatches == null) continue;
      return strMatches;
  } catch(e)
      app.alert("Processing error: "+e)
* tries to load given filename (extracted number)
* @param filename string of file which should be checked
* @param n number to iterate while checking for files
* @return true if file exists or false if not
function checkIfFileExists(filename, n) {
    var existingDoc = false;
    try {
        if( n == 0) {
            var checkDoc = app.openDoc({cPath : "../GAG-out/"+filename+"-001.pdf"});
        } else { 
            var checkDoc = app.openDoc({cPath : "../GAG-out/"+filename+"-001_"+n+".pdf"});
        checkDoc.closeDoc();
        existingDoc = true;
    } catch (e) {  
         app.alert("Processing error: "+e)
    if( existingDoc == true ) {
        n = n+1;
        n = checkIfFileExists(filename, n);
    return n;
var filename = ExtractFromDocument(idNumber);
if(filename == null || filename == undefined) {
  filename = Math.round(Math.random()*999999999999);
  this.extractPages({nEnd:(this.numPages-1), cPath : "../GAG-out/n_"+filename+".pdf"});
} else {
    fileExistence = checkIfFileExists(filename, 0);
    if(fileExistence != 0) {
        this.extractPages({nEnd:(this.numPages-1), cPath : "../GAG-out/"+filename+"-001_"+fileExistence+".pdf"}); 
    } else {
        this.extractPages({nEnd:(this.numPages-1), cPath : "../GAG-out/"+filename+"-001.pdf"});

Answer 1

Sorry, I marked it as bold text but unfortunately it happens to be unformatted
It's the app.openDoc within my function checlIfFileExists:
try {
        if( n == 0) {
           var checkDoc = app.openDoc({cPath :  "../GAG-out/"+filename+"-001.pdf"});
        } else  { 
           var checkDoc = app.openDoc({cPath :  "../GAG-out/"+filename+"-001_"+n+".pdf"});
         checkDoc.closeDoc();
        existingDoc = true;
     } catch (e) {  
         app.alert("Processing  error: "+e)