tzinfo_timezone/tzinfo can't modify frozen object

Hi.

I get the following error off and on in my app. I'm running latest
EdgeRails in development mode, and use the tzinfo_timezone plugin and
the tzinfo 0.3.3 gem.

I've checked line 210 in tzinfo_timezone.rb but cannot relate that to
an object modification in tzinfo. Any tips much appreciated.

ActionView::TemplateError (can't modify frozen object) on line #29 of
app/views/tickets/my_active_tickets.rhtml:
26: <%=link_to truncate(ticket.description,90,'...'),
ticket_url(ticket), {:title => sanitize(ticket.description)}%>
27: <div class="subtext" style="margin-top:3px;
margin-bottom:14px;">
28: #<%= ticket.id%>
29: | Submitted
<%=format_date(@this_user.tz.utc_to_local(ticket.created_at))%> by <%=
name_or_me(ticket.submitter_id, Proc.new {ticket.submitter.name})%>

30: | <%=ticket.status%> <%if
ticket.ticket_type_id?%><%=ticket.ticket_type.downcase%><%end%>

31: <%if ticket.priority_id?%> | <%=ticket.priority%>
priority<%end%>
32: <%if ticket.linked_id%>

#{RAILS_ROOT}/vendor/plugins/tzinfo_timezone/lib/tzinfo_timezone.rb:210:in
`tzinfo'

#{RAILS_ROOT}/vendor/plugins/tzinfo_timezone/lib/tzinfo_timezone.rb:184:in
`utc_to_local'
    #{RAILS_ROOT}/app/views/tickets/my_active_tickets.rhtml:29:in
`_run_rhtml_47app47views47tickets47my_active_tickets46rhtml'