v3 cannot access external drive over wireless network

I have previously used v2.4 and accessed an external drive on my PC via a wireless net work from my laptop. Having installed v3 I can access all the shared folders on the PC but not the external hard drive. I can see it in the network but cannot read the files.
For the moment have reverted to v2 and all is back to normal. Both computers using Xp. Any ideas?