Disappearing php-connector in FCK Editor Resource Browser

This is an error I have seen on MODx 9.5 and on 9.6r1 running on Windows 2003 with Apache 2.2.4 and MySQL 5.0.33-log. Current PHP version is 5.2.1, but I’ve seen the error using PHP4 as well.
I don’t know which browser version was used for upload. It was probably an old version of MSIE.

After a failed image upload, the Resource Browser will not show any files or folders. After some searching on the server I found that the uploaded image was saved as a folder - containing the php connector files from the resource browser. The [modx_root]\manager\browser\mcpuk\connectors\* was moved and renamed to [modx_root]/resources/images/[imagefilename]/*

Can anyone explain to me why this happened and how to avoid the problem?

Regards
Pål (Paul)