I'm working on a projector file which accesses data through remote xml file online. Can I retain the previous data from xml file to display when there is no Internet connection using SWF Studio...
Yes. You can write data out in a number of ways using SWF Studio. Probably the one that makes the most sense for using XML is to write the data to a file using the FileSys plugin.
You will probably want to store the data in the user's data directory. That would be the safest place, since it avoids security issues on Vista and on other computers where the user has a restricted account.
Use the file moniker allusersappdata:// if you want to write to the All Users data directory.
For more information see ssCore.FileSys.writeToFile, File Monikers, and the ActionScript API.