I study the section http://docs.sencha.com/extjs/6.5.3/g...g_started.html

I have install extjs sdk and ext cmd

In attempt to execute command in the terminal:
sencha app init [email protected] --modern MyApp

I receive a error:
[DBG] Verifying cmd version compatibility
[DBG] Version is compatible
[DBG] Invoking: sencha generate app -ext -modern myapp .
[ERR] The specified string cannot be converted into a valid namespace identifier
[ERR] Invalid namespace : myapp
at com.sencha.util.NameUtil.stringToNamespace(NameUtil.java:76)
at com.sencha.command.generator.GeneratorCommands$AppCommand.validateAppName(GeneratorCommands.java:680)
at com.sencha.command.generator.GeneratorCommands$AppCommand.execute(GeneratorCommands.java:420)
at com.sencha.command.app.AppCommands$InitCommand.execute(AppCommands.java:1819)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.sencha.util.MethodInvoker$Arguments.invoke(MethodInvoker.java:175)
at com.sencha.cli.Command.dispatch(Command.java:43)
at com.sencha.command.BasePluginCommands$BasePluginCommand.dispatch(BasePluginCommands.java:289)
at com.sencha.cli.Commands.dispatch(Commands.java:64)
at com.sencha.cli.Commands.dispatch(Commands.java:64)
at com.sencha.command.Sencha.dispatch(Sencha.java:80)
at com.sencha.command.Sencha.main(Sencha.java:147)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.exe4j.runtime.LauncherEngine.launch(LauncherEngine.java:65)
at com.install4j.runtime.launcher.UnixLauncher.main(UnixLauncher.java:57)


openjdk version "1.7.0_161"
OpenJDK Runtime Environment (build 1.7.0_161-b01)
OpenJDK 64-Bit Server VM (build 24.95-b01, mixed mode)

FreeBSD 11.1-RELEASE-p8 FreeBSD 11.1-RELEASE-p8 #0: Tue Mar 13 17:07:05 UTC 2018 [email protected]:/usr/obj/usr/src/sys/GENERIC amd64