Binary install of 3.5.13.2 on Xubuntu Lucid 10.04

I'm having a problem writing to files with konquerorsu. It is started with 
(kdesudo -c 'konqueror --profile filemanagement') then requests password, 
then opens ok.

I can create directories ok in the filesystem so it's obviously running as 
root, but I cannot save edited files, with kate, kwrite, and xfce's mousepad 
complaining about a permissions issue.

I have no problems with konquerorsu on other distros by the way.

I also started xfce's thunar from a shell with sudo thunar (on the TDE), and 
can save to files ok with that, so it's not some global problem about saving 
to files.

Any suggestions as to how to resolve the problem?

Thanks.

Nigel.