Some requirements may differ depending on how and where you got Soaplab from. But most requirements are universal.
Soaplab2 should work on any platform because it is written in Java. But keep it mind that Soaplab is just a Web Services gateway to the analysis tools (such as EMBOSS) that you wish to provide. These tools need also to be runnable on the same machine where you install Soaplab2.
Install JDK Java 1.5 or later.
Soaplab2 is about Web Services - and Web Services are web applications run in a servlet container. The development of Soaplab2 was mostly done by using the Apache Tomcat 5. But other container should work, as well.
The Ant is a Java tool for building, executing and playing with Java (and perhaps other, as well) programs. Soaplab2, as most of any Java programs, uses it a lot.
In the time of writing this, however, the Soaplab2 beta version does not have yet support for mySQL.
In the time of writing this, the Soaplab2 beta version still uses Perl for converting ACD files (those describing analyses that will be provided as Web Services) to XML files. The Perl is, however, not used when the services are run.
Also, Soaplab2 is distributed with few testing "analysis" (like echoing command line parameters, or copying input file to an output file) - and those are written in Perl.