Darcs just told me to report a bug:

$ darcs add pyweave
Yikes, pending has conflicts!
darcs: bug in darcs!
There was an attempt to write an invalid pending!
...

The Problem seems to be with:
$ darcs mv x y
$ darcs record
$ darcs add x

I expected the record in between avoids any conflict. After an optimize
the add succeeds.

Here is more data:

$ cat _darcs/patches/pending_buggy
{
adddir ./scripts
move ./pyweave ./scripts/pyweave
adddir ./pyweave
addfile ./CHANGELOG
addfile ./INSTALL
addfile ./LICENCE
addfile ./README
addfile ./scripts/pyweave/__init__.py
addfile ./tests.py
}

$ darcs --exact-version
darcs compiled on Jan 17 2006, at 03:05:19
unknown
(i use the Ubuntu Dapper version)

I haven't checked darcs-stable, but this bug no longer exists in darcs unstable
(or I misunderstood your directions as to how to reproduce it).

David

I can't reproduce it with 1.0.8 or currenet darcs-stable either.

likely fixed in 1.0.9 (or 1.0.8)