WSIF generally requires WSDL4J and XML parser that implements JAXP (such as Xerces2). For detailed list of required and optional JAR files and how to obtain them please take a look in lib/ subdirectories. Each subdirectory has short README file that explains how to get needed JAR file if you do not have them already on your CLASSPATH. Check detailed list of requirements.
There are two possibilities: use your preferred verion of ANT but you are responsible for setting CLASSPATH or use provided scripts that automate building and CLASSPATH setting.
Obtain all the necessary jar files as listed in the prerequisites.
Set required environment variables, including, JAVA_HOME, ANT_HOME.
From the root directory of wsif (where build.xml is located), run
ant -Dwsif.build.classpath=<classpath> <target>
where <classpath> contains the location of the preequisite JAR files
and, where <target> is one of the following:
If you downloaded the source distribution you need to make sure you have all prerequisite jars available under their respective subdirectories within the lib directory; the README files in each subdirectory will point you to a location where you can download the jar.
If you downloaded the binary distribution, most of necessary jar files are already included in lib directory. You will only need to download activation.jar and put it into lib/activation (see README), mail.jar and put it into lib/javamail (see README) and optionally j2ee.jar or other jar file with J2EE APIs (see README) to compile EJB and JCA providers (all of those files must be downloaded separately as they can not be distributed).
Then use build script (./build.sh on UNIX or build.bat on Windows) to rebuilt WSIF (see list of targets above).
After building, if you want just to run samples you can simply call classpath script (on Windows use classpath.bat on UNIX use source classpath.csh if you use TCSH or source classpath.sh if you use BASH) and you will have all required jar files on CLASSPATH, then you can proceed with running samples.