java.io.IOException: Error running exec(). Commands: [cd, sdcard/.yasmin] Working Directory: null Environment: null

I am not sure that this will fix your problem, but AFAIK, each call to exec() creates a new shell. A possible solution is to do the following:

1. Get the process of the exec() using: Process p = Runtime.getRuntime().exec(...).
2. Grab the process inputStream using p.getInputStream();.
3. Run the second command.

also note that you are trying to access the sdcard as you were in root folder and in a hardcoded path, consider the following:

Process p = Runtime.getRuntime().exec("cd /sdcard/.yasmin");

Or even better:

Process p = Runtime.getRuntime().exec("cd " + Environment.getExternalStorageDirectory() + "/.yasmin");

Hope it'll help!

you should use Runtime.getRuntime().exec("sh -c cd /sdcard/.yasmin");