content: counters(tocitem, ".");
is supposed to produce numbers like
1
2
2.1
2.2
2.2.1
2.2.2
2.2.2.1
etc.
It produces instead
1
2
2.1
2.2
2.21
2.22
2.22.1

Test case:
http://hsivonen.iki.fi/test/prince-counters/toc.xhtml
Works as expected in Gecko, WebKit and Opera.

Actual results from Prince Prince 6.0 (alpha 2007-01-16):
http://hsivonen.iki.fi/test/prince-counters/toc.pdf

Info about workarounds would be appreciated if there are workarounds.

That's odd; it looks like a bug in the Prince 6.0 alpha, as Prince 5.1 handles it correctly. Thanks for letting us know!

We have fixed this bug in the latest alpha version of Prince 6.0.

Excellent. Thank you.

The new alpha came at a very convenient time considering my upcoming publication.