You say:

# Access control
        
           clients => [
              # Accept the following addresses as clients
              { mask => '^999\.999\.999\.999', accept => 1 }, ## Sun S
+olaris box
              { mask => '^999\.999\.999\.9',   accept => 1 }, ## my of
+fice computer
              { mask => '^99\.99\.99\.99',     accept => 1 }, ## my ho
+me computer
              # Deny anyone else
              { mask => '.*',                 accept => 0 }
           ]
        }
[download]

Those don't look like netmasks or addresses. I suspect you are looking for numbers in the range 0-255.

$ man DBI::ProxyServer # Your Friend

After Compline,
Zaxo