Hi People,

I got a function which creates an attachment on a visualforce page. The functionality is working when i call the button from a apex button.
Now i overwrite the chatter save button to get the functionality on this button. When i use this button i get the error:
An error has occurred {faultcode:'UNKNOWN_EXCEPTION', faultstring:'UNKNOWN_EXCEPTION: Site under construction', }

The javascript code of the function is:

<script> 
    Sfdc.canvas.publisher.subscribe({name: "publisher.showPanel",
        onData:function(e) {
            Sfdc.canvas.publisher.publish({name:"publisher.setValidForSubmit", payload:"true"});
    }});
    Sfdc.canvas.publisher.subscribe({ name: "publisher.post",
        onData:function(e) {
            uploadFile();
    }}); 
</script>
	    <script>

        
    function uploadFile()
	{       
    $('#working').toggle();
    sforce.connection.sessionId = "{!$Api.Session_ID}";
    
    var cost = document.getElementById('costs').value;
    var details = document.getElementById('details').value;
    var input = document.getElementById('file-input');
    var parentId = 'a5ZL00000000CF7';


    var filesToUpload = input.files;
    
    if(filesToUpload.length == 0){
        alertify.error('No Attachment Found')
        $('#working').toggle();
    }

    for(var i = 0, f; f = filesToUpload[i]; i++)
    {
        var reader = new FileReader();     

        // Keep a reference to the File in the FileReader so it can be accessed in callbacks
        reader.file = f; 

        reader.onerror = function(e) 
        {
            switch(e.target.error.code) 
            {
                case e.target.error.NOT_FOUND_ERR:
                    alertify.error('File Not Found!')
                    $('#working').toggle();
                    break;
                case e.target.error.NOT_READABLE_ERR:
                    alertify.error('File is not readable')
                    $('#working').toggle();
                    break;
                case e.target.error.ABORT_ERR:
                    break; // noop
                default:
                    alertify.error('An error occurred reading this file.')
                    $('#working').toggle();
            };
        };     

        reader.onabort = function(e) 
        {
            alertify.error('File read cancelled')
            $('#working').toggle();
            
        };

        reader.onload = function(e) 
        {
            var att = new sforce.SObject("Attachment");
            att.Name = this.file.name;
            att.ContentType = this.file.type;
            att.ParentId = parentId;
            att.Description = 'Prijs:' + cost + '-Omschrijving:' + details;

            att.Body = (new sforce.Base64Binary(e.target.result)).toString();

            sforce.connection.create([att],
            {
                onSuccess : function(result, source) 
                {
                    if (result[0].getBoolean("success")) 
                    {
                        console.log("new attachment created with id " + result[0].id);
                        alertify.success('Nieuwe onkosten zijn toegevoegd')
           				setTimeout(closeAction, 3000);
                    } 
                    else 
                    {
                        console.log("failed to create attachment " + result[0]);
                    }
                }, 
                onFailure : function(error, source) 
                {
                    alertify.error("An error has occurred " + error)
                    console.log(error);
           			$('#working').toggle();
                }
            });
        };

        reader.readAsBinaryString(f);
    }
}
    function closeAction()
    {
        Sfdc.canvas.publisher.publish({name: "publisher.close", payload:{ feed:"true", refresh:"true"}});
    } 
</script>

Anyone got any idea?