Cannot access Network

I am trying to set up a small business network a shared
internet connection (DSL) with a MS Base Station. All
went well until I tried to share files between the
computers. All computers can access the internet just
fine, but they cannot see each other and I cannot access
files on any of them. I have tried "ping", "net view".
I can ping the base station but not any of the
computers. If I try to view workgroup computers I get
the error message that my workgroup is not accessable and
that I may not have permissions to use the network
resource. I have run the Network setup wizard on every
computer. They all have unique names and are all part of
the same workgroup. I have been through the network
troublshooters more than once. PLEASE HELP. The systems
may not make it through the night. Thanks