Can not edit files from XP computer on linux

[prasanna shetye]

Hello
   I set up a Linux with samba. I can browse files located on XP computer. I can even create a new folder or file on XP computer from my linux computer. But when I open a XP file in linux editor it open as read only and I can not edit that file. Please suggest what settings required so that I can edit XP files directly on linux.
  I tried logging with same login details on XP as well as Linux but that does not work.

regards