Description of problem:
$ yum provides "*/librpmbuild.so"
Loaded plugins: allowdowngrade, downloadonly, fastestmirror, kmdl
Error: Caching enabled but no local cache of //var/cache/yum/updates-debuginfo/filelists.sqlite.bz2 from updates-debuginfo

Version-Release number of selected component (if applicable):
yum-3.2.21-2.fc10.noarch

How reproducible:
whenever needed cache file doesn't exists

Expected results:
I understand what's going on, but the average user won't.
a) This is not an error, on either the user's part or yum's--both are doing the right thing
b) This message gives no idea as to the proper course of action to continue

A better message might be something like:
"Sorry; I could normally handle this query for you, but to do that I need a cached file that can only be generated as root.  Please try rerunning the command as root."