Hi Justin,
Firstly, the context – WordPress v3.0, calendar version 1.6.3
Permalink structure : custom with /%postname%/
If I turned off “pretty urls”, it worked as expected.
When “pretty urls” is turned back on, the generated url is
[site url]/category/events/month – which does not follow the permalink defined structure.
I gave up trying to get it to work.
I have built my own Calendar page.
Simon