I can confirm that putting a list() around the generator allows the removal to proceed:

diff -r d2453f281baf Lib/packaging/install.py
--- a/Lib/packaging/install.py	Fri Jun 24 10:21:46 2011 +0100
+++ b/Lib/packaging/install.py	Fri Jun 24 12:48:33 2011 +0100
@@ -389,7 +389,10 @@
     dist = get_distribution(project_name, use_egg_info=True, paths=paths)
     if dist is None:
         raise PackagingError('Distribution "%s" not found' % project_name)
-    files = dist.list_installed_files(local=True)
+    # list_installed_files returns a generator, and we need the
+    # RECORD file itself closed so that we can move it - under Windows,
+    # you can't move an opened file
+    files = list(dist.list_installed_files(local=True))
     rmdirs = []
     rmfiles = []
     tmp = tempfile.mkdtemp(prefix=project_name + '-uninstall')


The error message does need fixing, though, for cases where something else has a distribution's files open.