Hi everyone,
I've got some issues using data loader from the command line.
I follow all steps described in the data loader guide and the procedure works fine!
Now I 'd like to set up the config.properties file to avoid inserting every time the infos of endpoint, password and username.
I 've created the properties file in this way 

#Loader Config
#Thu Sep 10 09:37:47 PDT 2009
sfdc.endpoint=https://login.salesforce.com
sfdc.username=xxx@yyyy.it.dev
process.encryptionKeyFile=C:\Program Files (x86)\salesforce.com\data loader\bin\password.txt
sfdc.password=7c70f134b4e7542523a22faf15569753671ea416756a75db

but when I throw the process in command line I receive  the following error

2016-10-14 17:25:39,951 INFO  [main] controller.Controller initLog (Controller.java:389) - Using built-in logging configuration, no log-conf.xml in C:\Program Files (x86)\salesforce.com\Data Loader\bin\log-conf.xml
2016-10-14 17:25:39,967 INFO  [main] controller.Controller initLog (Controller.java:391) - The log has been initialized
2016-10-14 17:25:39,967 INFO  [main] process.ProcessConfig getBeanFactory (ProcessConfig.java:104) - Loading process configuration from config file: C:\Program Files (x86)\salesforce.com\Data Loader\bin\..\samples\conf\process-conf.xml
2016-10-14 17:25:40,139 INFO  [main] support.AbstractApplicationContext prepareRefresh (AbstractApplicationContext.java:495) - Refreshing org.springframework.context.support.FileSystemXmlApplicationContext@a30797: startup date [Fri Oct 14 17:25:40 CEST 2016]; root of context hierarchy
2016-10-14 17:25:40,233 INFO  [main] xml.XmlBeanDefinitionReader loadBeanDefinitions (XmlBeanDefinitionReader.java:315) - Loading XML bean definitions from file [C:\Program Files (x86)\salesforce.com\Data Loader\bin\..\samples\conf\process-conf.xml]
2016-10-14 17:25:40,311 INFO  [main] support.DefaultListableBeanFactory preInstantiateSingletons (DefaultListableBeanFactory.java:557) - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@6e2eef: defining beans [ANTAW01F_Upsert]; root of factory hierarchy
2016-10-14 17:25:40,451 INFO  [ANTAW01F_Upsert] controller.Controller initConfig (Controller.java:327) - config dir created at C:\Program Files (x86)\salesforce.com\Data Loader\bin\..\samples\conf
2016-10-14 17:25:40,467 ERROR [ANTAW01F_Upsert] config.Config initEncryption (Config.java:756) - Error initializing encryption for key file C:Program Files (x86)salesforce.comdata loaderbinpassword.txt: Cannot Access Key File: C:Program Files (x86)salesforce.comdata loaderbinpassword.txt
2016-10-14 17:25:40,467 FATAL [ANTAW01F_Upsert] process.ProcessRunner topLevelError (ProcessRunner.java:238) - Unable to run process ANTAW01F_Upsert
java.lang.RuntimeException: com.salesforce.dataloader.exception.ControllerInitializationException: Error loading config file: C:\Program Files (x86)\salesforce.com\Data Loader\bin\..\samples\conf\config.properties.  Please make sure that it exists and is readable
	at com.salesforce.dataloader.process.ProcessRunner.run(ProcessRunner.java:112)
	at com.salesforce.dataloader.process.ProcessRunner.run(ProcessRunner.java:100)
	at com.salesforce.dataloader.process.ProcessRunner.main(ProcessRunner.java:253)
Caused by: com.salesforce.dataloader.exception.ControllerInitializationException: Error loading config file: C:\Program Files (x86)\salesforce.com\Data Loader\bin\..\samples\conf\config.properties.  Please make sure that it exists and is readable
	at com.salesforce.dataloader.controller.Controller.initConfig(Controller.java:360)
	at com.salesforce.dataloader.controller.Controller.<init>(Controller.java:110)
	at com.salesforce.dataloader.controller.Controller.getInstance(Controller.java:212)
	at com.salesforce.dataloader.process.ProcessRunner.run(ProcessRunner.java:110)
	... 2 more

I 've put the config.properties file in samples folder ( in data loader directory) and I checked many times it exists and it's readable!
Like I said before storing this information in process-conf.xml (without using config.properties file) the procedure works perfectly, so I'm asking where Am I wrong??
Any ideas?
Thanks in advace.
Alex