The SupportLink site does not seem to offer a manual installation download for Red Hat Enterprise Linux AS release 4 (Linux 2.6).
There have been no changes required to QSA for this platform since version 2.1 of the O/S, therefore the Linux 2.1 QSA installer is applicable to Linux 2.6.
Download the file you need as follows:
1. Login to SupportLink at www.quest.com and select Support/downloads.
2. For the product, select "Space Manager with LiveReorg".
3. Click on Linux and you are offered three download files, choose the required build that supports the Oracle version being used.