XP Wireless Networking Problems - Any Clues

Hi

I have several wireless clients on my network. They all seem to work fine
(if a little slow) when internet browsing etc via the wireless router. All
internet tasks seem to work ok with an occasional error.

The problem is when attempting to do windows networking stuff. File copy
operations between wired & wireless clients fail with the standard error
"The remote connection is no longer available". The same error can occur
when browsing resources on the wireless clients if the file structure is
complicated / large. In addition if a wireless client tries to open a large
file from a file server eg5Mb word document - the same error occurs. The
connection is not dropped as I can start the copy again, continuous ping etc
etc.

Is anyone else having this problem - I've tried several different brands of
wireless routers (access points) and wireless NIC's with no success.

Any clues would be appreciated - I need to automate the backup of these
wireless clients accross the network & my present view is that Windows XP
wireless networking is not up to the tast.

D