missing header files.

Hi, I have following issue and need some help.
I am using SEGGER Embedded studio for ARM Release 3.4 build 2018052200 36079 with latest SDK on window 10 (64). Most of the SDK's sample examples compile and work, But I have come across couple of them a). wireless_uart under 802_15_4 folder and b), cli example under Thread/experimental, They always compile but now and then when I try to run them with Go command under SES studio the File explorer window pops up, indicating "missing file". Add or remove for future. It shows up for several files and only way I can kill it, is by window "kill task" function. On restarting things will work then back to same issue. I searched for these missing files in window directory and some of them don't even exits on the file system... not sure how to solve this?
On another issue on ses's debug terminal - How do I input commands (such as setting ip address, per example) in case of cli example.
Thanks