SyncBack may be an alternate solution to look into as you have XP Home, although it would not be ideal by any means.
You would set up a two-way sync between a local folder on your computer (e.g. c:\local_cache) and the network share in question. You could then set up changes to replicate backwards and forwards every 5 minutes or so, depending on the number of files on the network share.
Giving the local folder a drive letter is easy enough using the SUBST command from the command line.
subst z: c:\local_cache for example.
If you are looking at a solution that offers realtime synchronizing (or caching), I think that would be a bit more tricky and would most likely involve software having to be installed on the actual computer hosting the shares. Take a look here on lifehacker for a bunch of suggestions. Not really an option if the network shares are hosted on a corporate server, but hey, there is always SyncBack.