opening shared files problem

I have just set up a wireless network and ADSL Internet on three PCs,
there are a couple of issues arising from this, but first here is the
setup :

Belkin Wireless ADSL Modem/ Router 54G
1 Desktop PC running XP Home, the Modem /Router connected via Cat5
Ethernet cable, ICS plus Canon i350 Printer [shared]
2.Notebook with XP Home - wireless
3.Desktop running XP PRO - wireless

The Broadband Internet works on all three PCs, shared folders are
viewable from all PCs except that we cannot open any files from the
Notebook or the XP PRO PC on the other PCs.
Error msg is "you do not have permissions to view these files,
contact your Network Administrator" [or wording similar]

None of the PCs have a logon password set, just a username, the XP
PRO PC is using the Administrator account instead of a limited user
account, [which I feel is a bad move for security reasons].So I created
two new user accounts on the XP PRO PC to match the other two PCs, but
when it rebooted only the two new accounts where available at the
logon screen. Plus all the Administrators folders & files had
disappeared when we logged on with one of the new accounts, system
restore got me back
When printing from XP PRO the status monitor opens and says "printer not
responding",
but we can hear it chugging away in the next room and it does
complete the print job.
So three questions:

1. Why did the Admin account disappear, how to prevent this.
2. how do I make the files in network shares available from all PCs .
3. is the print monitor error msg related to the files being
unavailable error

rgds
Li'l Roberto