4.1 to 5.03 upgrade flawless except builtin Tags sidebar crashes typo

Hi typo folks,

I’ve been running http://gridengine.info on a hand-built Typo 4.1
system for a long time and just got around to testing out a move to
Centos 5 Linux and a shiny new RAILS environment.

The upgrade experience was very pleasant; thanks!

The only install issues I encountered were due to missing extensions
in the Ruby 1.8.6 I built from source. Finding and fixing was pretty
easy.

The rake migration process was painless as well. The site refused to
start up at first but going into the admin view and deleting all of
the sidebar plugins fixed that.

One by one I added in my sidebar plugins (nothing exotic, just Static/
and Categories/)

The only thing that does not work is the built-in Tags plugin for the
sidebar. Whenever I add it to the site I crash the built in webserver.

Because my site tracks a particular piece of grid computing software,
some of my tags are software version numbers like “6.0” and “6.0u12”
etc. In the past I’ve had URL based tag schemes refuse to accept the
“.” character but I’ve never had any problems with the Tags sidebar
plugin before on Typo 4.1.

Could my use of “.” characters in article tags be the cause of this
error output in the new Typo 5.03? Any hints or tips would be
appreciated.

Regards,
Chris