upload file error (io error) from Safari and firefox

Hi all,

Before I get yelled at, I'll get in first, yup, I'm a newbie!

Also before i start, I'm a windoz person and is possibly part of the reason I can't sort this out on a mac.

I am helping a friend build a wikispace and whilst we can write text to it, we cannot upload any pictures to it any more. it did work a week ago though...

it comes up with <URL> picname.jpg error during upload - please try again (io error) in both safari and firefox

uploading pictures to facebook doesn't work anymore- maybe this is a clue too?

We are using mac osx 10.5.8.

If I use my PC and log in to the wikispace, we can upload pix no problems at all.

if anyone has any ideas for me it would be great - the person I am helping is a student doing her first project for the year!

thanks in anticipation