Hi @harm-shares, and welcome to the community!
We have seen this error a few times and it usually results from a problem that occurred during an installation of a samba package update. Based on your screenshot, it appears you are on a fresh Rockstor install (as you have the first time login screen in the background), is that the case?
If yes, I would assume you have a ton of updates to install. You might have started to do so as well… is that the case as well?
The solution for your problem usually lies in re-installing the libwbclient library, so I will guide you towards the following forum post for instructions on how to do so:
Feel free to read the rest of the thread as it also contains useful information.
Now, as you are running a new install (I believe), you will have a lot of updates to do as Rockstor installer is now rather old (will be fixed very soon). Make thus sure not to shutdown or reboot the system until all of these updates are complete otherwise you risk issues like the one you are seeing. I would thus recommend to either trigger the updates from the webUI and wait for a rather long time, or simply go through the command line and trigger them manually using yum update. The latter will give you full progress on the operation.
Hope this helps,