Make sure the jsf-api.jar (http://www.java2s.com/Code/Jar/j/Downloadjsfapijar.htm) is included in the classpath (for example, by adding it to the WEB_INF/lib directory of your application). Note that you probably will need jsf-impl.jar as well.
This may be a library duplication. You must have JSF library on only one end.(Server side or app side)
1)Check your Stand alone application server installed the JSF related libraries. If yes remove your application jsf libraries.
You can directly remove them fom web-inf/lib folder by deleting from the EAR or WAR.
2)Without do any changes to server end You can use following entry to force the app to use only web-inf/lib libraries.