[Puppet Users] Migrating from an older version of puppet. classes not found.

Hello!
I'm migrating from an older version of puppet (puppet --version =
0.25.4) to 2.6.2.

The current directory structure of puppet is:

puppet
init.pp, not being detected>

An example of one of the clasess/*.pp files is:
# Software required for "core" servers as per the service catalogue
# This is in addition to base software which is the minimum for a
running server

#
class admin_tools {
package { "screen": ensure => latest }
package { "lynx": ensure => latest }
package { "lsscsi": ensure => latest }
package { "dosfstools": ensure => latest }
}


The problem I'm having is puppet --test gives me:

err: Could not retrieve catalog from remote server: Error 400 on SERVER:
Could not parse for environment production: No file(s) found for import
of 'classes/*.pp' at /etc/puppet/manifests/site.pp:13 on node
zvsv02.opus.co.nz

My site.pp file looks like:
# Root manifest file. Must exist; everything gets included from here.
# Also includes some root level configuration (file buckets etc)

#NB: No default "node". If a client doesn't match, we want to know
about it, not carry on blithely

import "common"
import "classes/*.pp"

<bunch of declared nodes>

I'm confident the nodes are properly formatted so I have committed them.
The the problem I find is if I comment out import "classes/*.pp" then I
don't get the error about importing the classes/*.pp, but then the nodes
can't import the .pp files that are located inside the classes directory
because it hasn't been imported.
So I guess my question is, how can I get puppet to import all these .pp
files (which I assume are classes) so that nodes can find them?