Redmine

There is an unexpecting problem.
We are using Remine more than 4 month.

Environment:
Redmine 1.3.2 Stable
Rails V2.3.14
RubyGems v 1.6
Rake 0.8.7
Rack 1.1.1

I've configured an automatic e-mail fetching from pop3 server.All works fine, but yesterday automatic email fetching feature stoped.
When I try to run
rake redmine:email:receive_pop3, a've got an error
Stack level too deep.
I restarted the server, uninstall all plugins, reinstall them again, try to run rake dm:migrate and so on.
All working fine, except email fetching.
The problem was solved by cleaning mailbox.
Today, i've got another problem

undefined method `count' for nil:NilClass

I try to configure automatic fetching email system to another mailbox - all working.
Then I send about 5 messages to this new mailbox - and get Stack level too deep message again.

Now I've cleaned both mailboxes, but it seems to me, than the problem will come again.

Can somebody help me?