Sencha Cmd v5.0.2.270 - Failed creating background process

I created my app with

Code:

 sencha generate app -ext MyApp myapp

Had no errors.

After this line I changed to my app folder

and after

Code:

tried sencha app watch

I have the following errors

[INF] appending sass content to C:\Users\cata\PhpstormProjects\ex1_extjs5\myapp/build/temp/development/MyApp/sass/MyApp-all.scss.tmp

[INF] executing compass using system installed ruby runtime

[ERR]

[ERR] BUILD FAILED

[ERR] com.sencha.exceptions.ExProcess: Failed creating background process

[ERR] at com.sencha.command.environme

[ERR] nt.AppOrPackageEnvironment.execute(AppOrPackageEnvironment.java:592)

[ERR]

[ERR] Total time: 5 minutes 34 seconds

[ERR] The following error occurred while executing this line:

C:\Users\cata\PhpstormProjects\ex1_extjs5\myapp\.sencha\app\build-impl.xml:246: The following error occurred while executing this line:

C:\Users\cata\PhpstormProjects\ex1_extjs5\myapp\.sencha\app\watch-impl.xml:56: The following error occurred while executing this line:

C:\Users\cata\PhpstormProjects\ex1_extjs5\myapp\.sencha\app\build-impl.xml:282: The following error occurred while executing this line:

C:\Users\cata\PhpstormProjects\ex1_extjs5\myapp\.sencha\app\sass-impl.xml:155: The following error occurred while executing this line:

C:\Users\cata\PhpstormProjects\ex1_extjs5\myapp\.sencha\app\sass-impl.xml:168: com.sencha.exceptions.ExProcess: Failed creating background proce

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Sencha Cmd v5.0.2.270 - Failed creating background process