I was just wondering if this has been solved yet, as I seem to be facing the same problems as AquiloNow.
following up on what YupYup said is it possible this is build 7057's fault. I am running Windows 7 x64 build 7057 and these networking problems apply to me too.
Both a Windows Xp Home (wireless laptop) and Windows XP Pro (wired desktop) cannot network with my wired windows 7 desktop. both XP computers see the 7 desktop, but give that same error as Aquillo (not accessible might not have permission etc) showed IF
i try to access a folder that is based on the same harddrive that windows is installed in. IE I cant access the Desktop folder or My Documents folder that i shared BUT
i can access a seperate hard drive that i shared (the D drive) that is installed on the Windows 7 machine.
the windows 7 computer cannot see either windows XP computer, or the shared printer that is on the XP Pro desktop, but it can see the two vista laptops that are also on the network and can access them just fine. everyone plays nice except windows 7 and XP.
thanks for the patience if you read all that!