Issue:
Following is an exception which is threw when you setup Siebel 8.1 SIA.
Exception:
(Dec 24, 2009 1:49:27 PM), Setup.product.install, Utility, msg1, Launching: hostname
(Dec 24, 2009 1:49:58 PM), Setup.product.install, CheckPrerequisites, msg1, Windows.ADCLIENT.OS required version 5.0.2172.1, version found: 5.1.2600.2180
(Dec 24, 2009 1:49:58 PM), Setup.product.install, CheckPrerequisites, err, Windows.Word.APP required version 9.0.0.0, no version found
(Dec 24, 2009 1:49:58 PM), Setup.product.install, CheckPrerequisites, wrn, Windows.Word.APP is not installed. "Please install Microsoft Office 2000 or above, to enable Siebel eDocuments server."
(Dec 24, 2009 1:50:31 PM), Setup.product.install, com.installshield.wizard.platform.win32.Win32ProductServiceImpl, msg1, installing Siebel Files (bean_Gateway/MAIN/MAIN)
(Dec 24, 2009 1:50:32 PM), Setup.product.install, SiebelFiles, err, java.util.zip.ZipException: unknown compression method
STACK_TRACE: 21
Solution:
According error tip, you need install Microsoft Office 2000 or above, because that needed by eDocuments Server.