Well, my system satisfies the minimum dependencies specified here:
http://calibre-ebook.com/download_linux
More specifically (required version in parentheses):
- Python: 2.6.5 (>=2.6)
- Python Imaging Library: 1.1.7 (>=1.1.6)
- Qt libraries: 4.6.3 (>=4.6)
- PyQt: 4.7.4 (>=4.7.0)
- python-mechanize: 0.2.2 (>=0.1.11)
- ImageMagick: 6.6.3.0 (>=6.5.9)
- xdg-utils: 1.0.2 (>=1.0.2)
- lxml: 2.2.7 (>=2.2.1)
- python-dateutil: 1.5 (>=1.4.1)
- cssutils: 0.9.7b3 (>= 0.9.7a3)
- BeautifulSoup: both 3.0.8.1 and 3.1.0.1 [not sure which is used] (>=3.0.5)
- dnspython: 1.8.0 (>=1.6.0)
- poppler: 0.14.1 (>=0.12.0)
- podofo: 0.8.1 (>=0.7)
- libwmf: 0.2.8.4 (>=0.2.8)
- chmlib: 0.40 (>=0.40)
As such, the versions I have match the required specification. It is possible that one of the versions I have is _too_ new, but in that case Calibre should specify upper bounds and not just lower bounds.