Using Django 1.2.1, any use of blocktrans breaks my template. Eg
{%blocktrans%}text{%endblocktrans%}
Results in:
Django Version: 1.
Just add that to your built-in tags like this, instead:
# in urls.py template.add_to_builtins('django.templatetags.i18n')
Any tag I'm using in multiple templates, I just load into there.