FCKeditor Resources Browser - upload vs. browser settings, problem

Hi,

I notice problems with FCKeditor Resources Browser. On my machine everything works (upload works) but in some cases editors cannot upload files - they’re getting errors. I think that it’s because of browser settings.

What should be the settings for web browser to properly work with FCKeditor?

Or maybe there is something else I should configure to ensure FCKeditor Resources Browser works properly on various PCs?

Thanks for any help.
Greg