I have two different types of issues with Firefox and IE. I just installed the trial version of DMX 4 on my local machine (Vista) which has DNN 4.5.5 installed.
Firefox v2 - I was able to upload a document, but the double click and right click functionality does not work. When I double click the screen refreshes, but the file is not opened. When I right click on a file I see the usual browser menu instead of the DMX menu.
IE v7 - When I double click on a file it opens in a new web browser window, but the word and excel test files I uploaded are garbled. When I right click and choose to "Open in Excel" I get the error, "Automation server can't create object". For this last error I found a post that suggests checking the WebDav forum, so I'll read more over there, but is this something that could be addressed during the installation of the module?