The installation notes did not mention any compatibility with Struts 2.

Compatibility

• Struts-Layout 1.0 works with Struts 1.0 and 1.1. However, note that due to an inheritage change between Struts 1.0 and Struts 1.1, Struts-Layout must be recompiled to work with struts 1.0.
  
• Struts-Layout 1.1 works with Struts 1.1 and 1.2.
  
• Struts-Layout 1.2, 1.3 and 1.4 works with Struts 1.2 and 1.3. It can also work with Struts 1.1 if you use the special compatibility jar.

https://web.archive.org/web/20111227074645/http://struts.improve-technologies.com/install.html

This library is not available anymore, but if somebody still has the JAR file for Struts-layout 1.4 that could share, I would be appreciated.