First thing to try is to connect using an Ethernet cable temporarily
and get all updates plus hardware updates ( these should start up
automatically when a connection is seen ). In most cases this enough
to bring a recalcitrant USB dongle to life :-)

The USB Dongle is working OK as I can get an internet connection,I
am sorry that I didn't explain the problem better..however here it is
again....
Three of my PCs are succesfully sharing an Epson SX515W Wireless
Printer/Scanner over my WiFi Network.Unfortunately the PC running Linux
Mint 11 connects to the Wifi Network and the WWW,however it will not connect
properly with the Epson SX515W Printer[even though I have installed the
correct Linux Avansys Drivers Print and Scan.[.same as Ubuntu 11.04]The
Wireless Printer is found ok/shared and enabled,but there is a Printer icon
with a yellow exclamation mark showing in the bottom menu toolbar of the
homepage,which when clicked shows the Printing Status(my jobs) ie One job is
pending another job is processing?..PRINTER WARNING.on both.it will not scan
either.
Any ideas why this should happen?
[Netgear 934G Wifi Router..Ralink USB Dongle SKY ISP Mint 11 OS Up to date.

I'd surmise that Mint 11 is missing some networking packages that are
present in Ubuntu 11.04 since the Avansys driver appear to be fine on
that. Can you access other shared folders on the network with Mint 11
and can other system access shared folders in Mint 11 ?

barry not sure will have to check and get back to you..

Ok - so there's something not 100% with networking in general and that
would explain the failure of getting the wireless printer to connect.

Next question is whether you got any error messages from Mint when you
tried to access the network or did it just ignore you ? Usually when
accessing networks for the first time Ubuntu will prompt you to get
the required packages for this - have you ever got anything like that
from Mint 11 and what was the procedure on the other Ubuntu 11.04
boxes when accessing the printer / network shares for the first time ?

What USB wireless Ethernet device do you have? What version of Ubuntu are
you using. I have a D-Link DWA-125. Ubuntu 11.04 recognizes it when the OS
is installed, no modifications or additions to Ubuntu needed. !0.04 and
10.10 need a modification/addition to the setup then it works fine. It is
working now isn't it. (Posted using a D-Link DWA-125)

Also try,
Do a Google search for Ubuntu and your adaptor, for me it would be Ubuntu &
DWA-125

I had the same problem... i surfed and asked and it just seems there is
hardware issues with wireless in 11.04 sooooo i installed 10.10 and it
worked fine... so i would backstep to the previouse releases