Open all .indd files from the selected folder

There are a couple of conceptual errors in your script, which may be the reason you couldn't get it to work. This line

myFile.name.match(/\.indd$/)

does "nothing". It tries to find a match for the variable "myFile", but then it doesn't 'do' anything with the result -- there is no "logic" surrounding the statement. So the next line,

myFiles.push(myFile);

will always be executed. You probably meant something like

if (myFile.name.match(/\.indd$/))

   myFiles.push(myFile);

.. Javascript does what it gets told and does not do "what you mean".Next, another error is this:

app.open(myFiles)

I had to check this, but you are right: app.open can open an array of files -- I only use it to open just one file at a time. However, you placed this statement inside the main loop! So for every file in the loop, InDesign attempts to open *all* files, again and again.

With these changes, you can get your original script running properly.

By the way, note that your question has been answered before. A nice in-depth discussion is in http://forums.adobe.com/thread/791888 -- of particular interest is the entire "when is a file an InDesign file" sub-discussion.

Here is a line that works ... but I would advise you not to use it. Please try to fix your own script! Only if you understand the basic concepts, then you can advance to this:

app.open(Folder(Folder.selectDialog( "Select a folder with InDesign files")).getFiles(function(f) { return f instanceof File && !f.hidden && (f.name.match(/\.indd$/i) || f.type.match(/^IDd/)); } ));

Here is an example of how to open all indd-files from the selected folder and its subfolders.

var files;
var folder = Folder.selectDialog("Select a folder with InDesign documents");
if (folder != null) {
    files = GetFiles(folder);
    if (files.length > 0) {
        // turn off warnings: missing fonts, links, etc.
        app.scriptPreferences.userInteractionLevel = UserInteractionLevels.NEVER_INTERACT;
        for (i = 0; i < files.length; i++) {
            app.open(files);
        }
        // turn on warnings
        app.scriptPreferences.userInteractionLevel = UserInteractionLevels.INTERACT_WITH_ALL;
    }
    else {
        alert("Found no InDesign documents");
    }
}
function GetFiles(theFolder) {
    var files = [],
    fileList = theFolder.getFiles(),
    i, file;
    for (i = 0; i < fileList.length; i++) {
        file = fileList;
        if (file instanceof Folder) {
            files = files.concat(GetFiles(file));
        }
        else if (file instanceof File && file.name.match(/\.indd$/i)) {
            files.push(file);
        }
    }
    return files;
}