rpm error " can't create transaction lock"

To: For users of Fedora Core releases <fedora-list@xxxxxxxxxx>
Subject: rpm error " can't create transaction lock"
From: Nina Pham <nina@xxxxxxxxxxx>
Date: Fri, 02 Jul 2004 14:07:37 -0700
Reply-to: nina@xxxxxxxxxxx, For users of Fedora Core releases <fedora-list@xxxxxxxxxx>
User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6) Gecko/20040113

HI, what does it mean when I do #rpm -U software.rpm, it turns backs with message "error: can't create transaction lock" ?

Follow-Ups:
- Re: rpm error " can't create transaction lock"
  - From: Pedro Fernandes Macedo
- Re: rpm error " can't create transaction lock"
  - From: Nina Pham