It seems like the “stable channel” repository is active in your system. However, the current stable 4.1.1-0" only" runs under Leap 15.3, and the above error message indicates it’s looking for the rockstor-stable repository under Leap 15.4 (which it won’t find for now, since we’re still working through the Release Candidates on the testing channel before the next stable version is release in the stable channel, hopefully shortly).
You mentioned above that you have 4.5.8-0 installed. After the installation of 4.5.8 did you set the stable channel or the testing channel?