Switch environment using -E parameter

I am trying to run the tests from Hudson using ANT with -E parameter to switch environment and get the error :

org.apache.commons.cli.UnrecognizedOptionException: Unrecognized option: -E
- Could not find jfxrt.jar. Internal browser will be disabled.
SoapUI 5.1.2 TestCase Runner
at org.apache.commons.cli.Parser.processOption(Parser.java:253)
- org.apache.commons.cli.UnrecognizedOptionException: Unrecognized option: -E
at org.apache.commons.cli.Parser.parse(Parser.java:170)
- An error occurred [Unrecognized option: -E], see error log for details
- org.apache.commons.cli.UnrecognizedOptionException: Unrecognized option: -E
at org.apache.commons.cli.Parser.parse(Parser.java:114)
org.apache.commons.cli.UnrecognizedOptionException: Unrecognized option: -E
at com.eviware.soapui.tools.AbstractSoapUIRunner.initFromCommandLine(AbstractSoapUIRunner.java:137)
at org.apache.commons.cli.Parser.processOption(Parser.java:253)
at org.apache.commons.cli.Parser.parse(Parser.java:170)
at com.eviware.soapui.tools.AbstractSoapUIRunner.validateCommandLineArgument(AbstractSoapUIRunner.java:106)
at org.apache.commons.cli.Parser.parse(Parser.java:114)
at com.eviware.soapui.tools.AbstractSoapUIRunner.runFromCommandLine(AbstractSoapUIRunner.java:97)
at com.eviware.soapui.tools.AbstractSoapUIRunner.initFromCommandLine(AbstractSoapUIRunner.java:137)
at com.eviware.soapui.tools.AbstractSoapUIRunner.validateCommandLineArgument(AbstractSoapUIRunner.java:106)
at com.eviware.soapui.tools.SoapUITestCaseRunner.main(SoapUITestCaseRunner.java:117)
at com.eviware.soapui.tools.AbstractSoapUIRunner.runFromCommandLine(AbstractSoapUIRunner.java:97)
at com.eviware.soapui.tools.SoapUITestCaseRunner.main(SoapUITestCaseRunner.java:117)

Why i am getting this error ?
and, Where can i fount the error log for details ?

Thanks a lot,