QUESION: 

If I open a MS-Office document inside Firefox it makes OpenOffice startup  
but then results in an error message about not being able to read the 
file.

ANSWER:

This is most likely caused because the filename contains strange characters
like spaces or % signs. 

It is not Open Office itself that has problems with this but the plugin 
used to start Open Ofice (in our case "plugger"). Of course you can always
download using the right mouse and then open the file from your filemanager,
but you can also force Firefox to permanently bypass the plugin altogether
by using the following trick(s) :

1) Type in the Firefox URL bar : about:config

2) Search for a property called 
"browser.download.hide_plugins_without_extensions"

This property is most often set to "true". Just click on it to toggle it to 
"false" so that you'll be able to see ALL plugin mimetypes and not only a 
subset.

3) Go to Edit -> Preferences -> Downloads -> View/Edit Actions and search 
for the mimetype of the problematic file.

As an example : for a MS-Word document the mimetype is application/msword 
or application/x-msword and for a MS-Powerpoint file it is 
application/mspowerpoint

4) Use "Change Action" to change the default action to simply 
use /opt/bin/swriter (or /usr/bin/abiword if you wish) instead of the 
plugin. Note that you have to specify the full path name.

From now on the download manager will download the file and then 
automatically open inside OpenOffice without problems.

BTW: I am not sure about MS-Windows but I think this procedure also 
largely applies to the MS-Windows version of Firefox.

Kees Lemmens,
March 2006.