We will take a closer look at these entries that clearly look to be inserted in the Hosts file in order to block access to the listed domains as the malicious hostnames are redirected to 127.0.0.1 (local address or localhost). We will correct this as of the next definition file update. The blocking may have been done by some other application that you may have installed and and it may also have locked(write protected) the Hosts file in order to protect it from changes (this can also be done by the Ad-Aware Hosts File Editor, by ticking "Write-Protect Hosts File"). The Ad-Aware 2008 Hosts File Editor can be reached via the Tools & Plug-Ins button.
Spybot Search & Destroy is an example of an application that let their users "Add Spybot S&D hosts lists" in order to block access to certain malicious sites. If the Hosts file is locked down by the application the entries cannot be removed for as long as the the lock(write-protection) is applied.
Thank´s for informing us about the issue!
As mentioned previously it will be corrected as of the next definition file update.
Here are the hostnames that Ad-Aware 2008 with Definitions 0122.0000 updated 09/18/08 at 7:26 AM (GMT-07:00 US Mountain time) reported as Critical Objects. Please note that my host file is the 08/06/08 version from MVPS HOSTS and is read-only, which is probably why Ad-Aware could not remove them:
563 Redirected hostfile entry Misc 4
 IP Address: 127.0.0.1 Host Name: THEREALSEARCH.COM
 IP Address: 127.0.0.1 Host Name: INSTALL.XXXTOOLBAR.COM
 IP Address: 127.0.0.1 Host Name: 1-SE.COM
 IP Address: 127.0.0.1 Host Name: CRACKS.AM
 IP Address: 127.0.0.1 Host Name: IE-SEARCH.COM
 IP Address: 127.0.0.1 Host Name: ITSEASY.US