I ran into the same issue with TOS 5.1.2 on running on Redhat 2.6.32-220.el6.x86_64.
Here's the fix:
1) In your user's home directory, you should have a ".gnupg" directory, i.e. ~/.gnupg
2) Look for ~/.gnupg/gpg.conf. If it's not there create the file with a text editor. In my case, the conf file was not present.
3) Add the parameter "batch" to the conf file.
4) Rerun your Talend job....the password text box should be suppressed.
See 'man gpg' for more info.