I was trying to get the subwebs of a site collection by using AllWebs(), but was getting a permissions error when running the code as a non-Admin, even though that user had read permissions on all of the subWebs in the collection.

Thanks to a helpful person on a BB, the solution was to use GetSubWebsForCurrentUser() (http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.spweb.getsu…) instead of AllWebs().