Form Store Binder - undefined argument: rows

I am trying to modify environment variables via a form.

I am getting "Undefined argument: rows" following steps described in: Manage Environment Variable using Form

ERROR 28 Jul 2016 11:21:06 org.joget.apps.form.lib.BeanShellFormBinder - Error executing script
Sourced file: inline evaluation of: ``import java.util.Collection; import org.joget.apps.app.dao.EnvironmentVariableD . . . '' : Undefined argument: Rows : at Line: 49 : in file: inline evaluation of: ``import java.util.Collection; import org.joget.apps.app.dao.EnvironmentVariableD . . . '' : ( element , Rows , formData )

The load Binder works but not the store binder in the userview - how can i correctly define "rows"? what is the wrong with the provided code? here is the code:

import java.util.Collection;
import org.joget.apps.app.dao.EnvironmentVariableDao;
import org.joget.apps.app.model.AppDefinition;
import org.joget.apps.app.model.EnvironmentVariable;
import org.joget.apps.app.service.AppUtil;
import org.joget.apps.form.model.Element;
import org.joget.apps.form.model.FormData;
import org.joget.apps.form.model.FormRow;
import org.joget.apps.form.model.FormRowSet;
import org.joget.apps.form.model.FormStoreBinder;
import org.joget.commons.util.LogUtil;
import org.joget.plugin.base.PluginManager;

public FormRowSet store(Element element, FormRowSet rows, FormData formData) {
//check the rows is not empty before store it
if (rows != null && !rows.isEmpty()) {
AppDefinition appDef = AppUtil.getCurrentAppDefinition();
EnvironmentVariableDao environmentVariableDao = (EnvironmentVariableDao) AppUtil.getApplicationContext().getBean("environmentVariableDao");

//Get the submitted data
FormRow row = rows.get(0);

//Add / Update each Environment Variable
for (Object key : row.keySet()) {
String envId = (String) key;
String value = row.getProperty(envId);

if (!envId.isEmpty()){
EnvironmentVariable e = environmentVariableDao.loadById(envId, appDef);
if (e != null) {
e.setValue(value);
environmentVariableDao.update(e);
} else {
EnvironmentVariable e = new EnvironmentVariable();
e.setAppDefinition(appDef);
e.setId(envId);
e.setValue(value);
environmentVariableDao.add(e);
}
}
}
}

return rows;
}

//call store method with injected variable

return store(element, rows, formData);