Flash file upload issue with Flash player 10.1

I have a file upload script to upload pictures to a server. It has been working fine in all browsers but when I upgraded the Flash Player to 10.1 in Firefox 3.6.6 yesterday it stop working.

I retested with another computer and as soon as I installed the Flash Player 10.1 it stopped working.

I did some debbuging and noticed that the error return from the FileReference listener is I/O error.

It doesn't make sense because the file is in the server and it works fine in all other browsers.

I changed allowScriptAccess from "samedomain" to "always" without luck.

I also used absolute path in the upload URL. When I run it in my local development environment it works but it doesn't work in the production server. I have changed the security settings of the folders in the server to 777 and still doesn't work either.

What can it be? It works perfectly in other Flash Player versions.

The HTML that embeds the movie:

<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="http://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=8,0,0,0" width="550" height="300" id="test" align="middle">
<param name="allowScriptAccess" value="sameDomain" />
<param name="wmode" value="transparent" />
<param name="movie" value="uploader_.swf?id=<?=$owner_id?>&ga=<?=$ga_c at?>&sid=<?=$ukey;?>" /><param name="quality" value="high" /><param name="bgcolor" value="#ffffff" />
<embed src="uploader_.swf?id=<?=$owner_id?>&ga=<?=$ga_cat ?>&&sid=<?=$ukey;?>" quality="high" bgcolor="#ffffff" width="550" height="300" name="test" align="middle" allowScriptAccess="sameDomain" type="application/x-shockwave-flash" wmode="transparent" pluginspage="http://www.macromedia.com/go/getflashplayer" />
</object>

SWF:

var item:FileReference;
//...
//some code and processing of vars needed in the php script to store in the DB
//...
item.upload("upload.php?sid="+sid+"&am开发者_StackOverflow社区p;id="+uid+"&ga="+ga+"&seq="+ sequence); 

I don't think this problem has been solved yet...See https://bugs.adobe.com/jira/browse/FP-1044

[update]
Snapshot from a mirror of the Internet Wayback Machine

Right click on the movie and check your global settings, adjust as needed. I've had permission issues like those before since installing 10.1. Security is tighter.