Networking woes (file & printer sharing)

I have searched the forums for a solution to this; didn't find any that I hadn't already tried, so I decided to post a new thread.

Ok, so I have a couple of issues with my home network. I have 4 machines networked on a wireless network. Router is a Linksys WRT54G with WPA encryption using TKIP (if that makes any difference). One machine is running Win 7, one is running, Vista, and the other two are running XP Home. Both of the XP computers are using old Linksys WMP11 PCI wireless adapters. I will refer to the computers as W7MACHINE, VISTAMACHINE, XPMACHINE1, AND XPMACHINE2.

1. Ok, so my first problem is kinda simple. I'm trying to share my profile folder on W7MACHINE (C:\Users\Me) over the network. I have it set to share, permissions give everybody full access, but none of the other machines can access it. They can see it, but when they try to access it they get an error telling them access is denied. Password-protected sharing is disabled, by the way. Why can't I access it?

2. The second problem is really the biggie. I have a Lexmark X5270 connected to XPMACHINE2, and I want to set up the other computers so they can print on it. XPMACHINE1 prints on it fine, no problems. Neither the Vista nor the Win 7 machine, however, can install it via the Add Printer -> Network Printer utility. Both W7MACHINE and VISTAMACHINE have the drivers installed on them, however, the company has not released drivers for Win 7 yet. When the printer is physically connected to W7MACHINE, it works fine with the Vista drivers. Whenever I try to add the printer via the Add Printer->Network Printer utility, however, I get an error saying that Windows could not access the printer (error 0x0000000d). So, I tried the method that I found here and a few other places of telling the computer it's on a local port, creating \\XPMACHINE2\Printer as the port, then trying to install. However, all this does is give me an interminable "installing printer..." dialog box, which I have let run for over an hour with no results. When I cancel it, I have to end the task via the Task Manager.
XPMACHINE2 also has a printer connected to it, an HP OfficeJet 4200 Series, which both the Win 7 and Vista computers can access, print on, etc. just fine. So, why can't I access the printer on the other computer? Is the printer too old? Is the computer too old?

3. My third problem isn't very important, but it's bugging me. When I go to the network map in Vista or Win 7, both XP machines are listed down at the bottom of the map because "Windows could not place the following discovered device(s) on the network map". I've heard this has to do with the Link-Layer Topology thing, but both XP computers are running SP3, which was supposed to include that fix. I've tried the method for fixing it found here, but they still don't show up.
Oh, occasionally, when viewing the network map from the Win 7 machine, the Vista machine isn't placed on the map either. *scratches head*

Hope somebody(s) can help me!

#1. I just went through this exact same problem. Try reading Create Completly 'Open' Network Between Win7, Vista & X Basically, you need to go into Security tab and give ownership to everyone, or define a group.

I had to uncheck Internet Protocol Version 6 (TCP/IPv6) in my Local Area Connection Properties. Yours would be the wireless properties.

Your first 2 issues sound like NTFS permission problems - the "Security" tab. Like aem said.... you should try to create the same user accounts and passwords on all the machines. It really does make sharing a lot simpler.

If I add permissions for a user, then I should log on as that user from the other machines? Ok. But what if I have password protected sharing turned off?

About the printer - no, it does not have wireless capabilities. It's just connected to XPMACHINE2, which is on the network. XPMACHINE2 is using an old Linksys WMP11 wireless-b card, if that makes any difference. I don't see why it should, though - the other printer (connected to XPMACHINE) prints fine off of win7 as a networked printer. On vista, I have to do the local port dodge in order to get it to print, but neither of those methods works for the printer on XPMACHINE2.