Index: uploader.js
===================================================================
--- uploader.js	(revision 13936)
+++ uploader.js	(working copy)
@@ -16,6 +16,7 @@
 	// set params to uploader
 	this._eventQueue = [];
 	this.uploadCancelled = false;
+	this.flashReady = false;
 
 	this.params = params;
 	this._ensureDefaultValues();
@@ -26,6 +27,8 @@
 
 	this.uploadURL = params.uploadURL;
 	this.deleteURL = params.deleteURL;
+
+	this.enableUploadButton();
 }
 
 /* ==== Private methods ==== */
@@ -198,6 +201,21 @@
 	}
 }
 
+Uploader.prototype.enableUploadButton = function() {
+	var $me = this;
+
+	// enable upload button, when flash is fully loaded
+	this.queueEvent(
+		function() {
+			setTimeout(
+				function () {
+					$me.callFlash('SetButtonDisabled', [false]);
+				}, 0
+			)
+		}
+	);
+}
+
 Uploader.prototype.renderBrowseButton = function() {
 	var holder = document.getElementById(this.params.buttonPlaceholderId);
 	this.swf.write(holder);
@@ -515,6 +533,11 @@
 	// Queue the event
 	this._eventQueue.push(function_body);
 
+	if (!this.flashReady) {
+		// don't execute any flash-related events, while it's not completely loaded
+		return ;
+	}
+
 	// Execute the next queued event
 	setTimeout(
 		function () {
@@ -523,6 +546,21 @@
 	);
 };
 
+Uploader.prototype._executeQueuedEvents = function() {
+	var $me = this;
+
+	setTimeout(
+		function () {
+			$me._executeNextEvent();
+
+			if ($me._eventQueue.length > 0) {
+				$me._executeQueuedEvents();
+			}
+
+		}, 0
+	);
+}
+
 // Private: callFlash handles function calls made to the Flash element.
 // Calls are made with a setTimeout for some functions to work around
 // bugs in the ExternalInterface library.
@@ -585,16 +623,8 @@
 
 Uploader.prototype.onFlashReady = function() {
 	var $me = this;
+	this.flashReady = true;
 
-	this.queueEvent(
-		function() {
-			setTimeout(
-				function () {
-					// enable upload button, when flash is fully loaded
-					$me.callFlash('SetButtonDisabled', [false]);
-				}, 0
-			)
-
-		}
-	);
+	// process events, queued before flash load
+	this._executeQueuedEvents();
 }
\ No newline at end of file