I applied this patch that apparently corrects the problem:
--- /usr/bin/rundig~ 2009-07-27 06:03:09.000000000 +0200
+++ /usr/bin/rundig 2010-01-08 12:20:24.000000000 +0100
@@ -81,13 +81,13 @@
# These databases are semi-static, so even if pages change,
# these databases will not need to be rebuilt.
#
-if [ "`ls -t $COMMONDIR/english.0 $COMMONDIR/word2root.db 2>/dev/null | sed 1q`" = \
+if [ "`ls -t $COMMONDIR/english.0 $DBDIR/word2root.db 2>/dev/null | sed 1q`" = \
"$COMMONDIR/english.0" ]
then
$BINDIR/htfuzzy $opts endings
fi