Antix 8.5, fluxbox

When I use pcfileman, and select TOOLS >> Open Current Folder as Root, it never seems to let me open the current folder as root. Why is that?

You need to set pcmanfm to do so. In Edit->Preferences->Advanced, type in Switch user command

gksu %s

and close.

Sorry!

When I start pcmanfm, and go to Edit >> Preferences >> Advanced, all I see is this:

On-disk file name encoding (currently set to UTF-8)
Terminal (with a drop down list, currently nothing selected)
Use SI decimal prefixes instead of IEC binary prefixes (the check box is currently checked)

There is nothing called"Switch user command" that I can type in.

On a lark, I typed gks= %s in the Terminal field, but it didn't seem to work - even though I entered my password, when I tried to (harmlessly) alter a file, it said I didn't have permission.

Thoughts?

You must be using the old pcmanfm 0.5. It's current version is 0.9.7 now and has that option anticapitalista said.
You can either upgrade your system and get it or if you don't want to do so you can set up /etc/sudoers so you enable that feature in your old version of pcmanfm.
For the latter, open a terminal, login as root and run visudo, then you may find a line for pcmanfm, just remove the comments (the # sign at its beginning), save (ctrl+o), exit (ctrl+x) and then it should work.

that appears to work, thanks.