To connect to the app from Windows XP, you will need to add a new network place to My Network Places in Windows Explorer.

This can be done by right clicking on My Network Places and selecting Map Network Drive.... In the Map Network Drive dialog, click on the link which says Sign up for online storage or connect to a network server. The Add Network Place Wizard will be shown.

Press Next. 

Make sure the Choose another network location entry is selected and press Next.

Make sure that the app is running on your device and that the Enable File Sharing is turned on from the Settings page.

Enter the address of your device into the Internet or network address field in the Add Network Place Wizard. For example http://192.168.0.53:8080

Press Next.

Enter a name for your device to be displayed for the new network place and press Next.

Press Finish.

You should now be able to access the app's files from within Windows Explorer.