Builds, tests, and runs the project webclient. Conditions for compilation have not been met. Have you verified that the property browser.bin.dir has been set to the binary directory of the host browser in the webclient.properties file? The current value of this property is: ${browser.bin.dir} and this directory must contain the file ${so.prefix}xul.${so.extension}. Also, you must make sure the properties javaxpcom.jar and MozillaInterfaces.jar are valid. javaxpcom.jar is currently ${javaxpcom.jar} MozillaInterfaces.jar is currently ${MozillaInterfaces.jar} org.mozilla.webclient.impl.WebclientFactoryImpl org.mozilla.webclient.impl.wrapper_native.WrapperFactoryImpl