Error 1200 on app.paste()

Cant post the whole Code, but here is the function i am using. It is working on two different machines. On the third machine it throws the error BUT only on the second file. The first file is pasted and positioned as it should. 

/**
 *  Copy all Items in file to destination document and position it with positionPasted();
 *  
 *  @9397041 File file - file to be copied
 *  @9397041 String pos - position on the file
 *  @9397041 String size - dimensions of the file
 *  @9397041 Document destDoc - destination document
 *  @Return 
 */
function placeLaserfiles(file, pos, size, destDoc) {
    var singleFile = app.open(file);

    var orientation = null;
    if (singleFile.width > singleFile.height) {
        orientation = "landscape";
    } else {
        orientation = "portrait";
    }

    for(var i = 0; i < singleFile.pageItems.length; i++) {
        singleFile.pageItems[i].selected = true;
    }

    app.copy();
    destDoc.activate();
    //alert("test");
    app.paste();

    positionPasted(pos, size, orientation, destDoc);
    singleFile.close(SaveOptions.DONOTSAVECHANGES);
    return;
}