I like this script very much and look forward to seeing it further developed! It reminds me on Emacs Org-Mode, but with the "familiarity" and convenience of Vim.
What I found is, that dates are sometimes rendered as for instance 2010-05-2999999999 instead of 2010-05-29, and I think changes of VimTask lines are not always reflected immediately in the _TRagQFL_ buffer following ":VimTasks".
I use a Windows XP (International) Service Pack 3 PC with German Keyboard and Vim 7.2 with the latest necessary scripts installed.
Thanx for developing this interesting script!
Small bug: version 0.03 of the script asks for version 3.19 of the viki script but the latest version is 3.18, so I guess it should ask for that version instead.