tags.py problem

I've just started playing around with pyblosxom and it looks pretty nice. 
I'm having an issue with the tags plugin though.  When I run 'pyblosxom-cmd 
buildtags', a tags file is made specified location.  It appears to have 
picked up the correct data too.  Furthermore, when I check my website in 
debug mode, the Request.get_data() dict has an entry 'tagsdata' that has the 
right information.  This goes away if I disable the plugin.

The problem is when I enable the tags plugin and turn off debug mode, I get 
the following message:
"A server error occurred.  Please contact the administrator."

When I disable the tags plugin, the site works fine.

This is on 1.5rc2 with the tags.py that came with the distribution.

Any ideas?

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