What version of RM/COBOL are you using, and what version of Windows? Is this 32-bit or 64-bit RM/COBOL?
Did it previously work and then stop working?
Or is this a fresh installation -- and if so, was it installed directly or from the network?
If not a fresh system, something happened to the installation. Try running the following commands as an administrator:
32-bit: "C:\\Program Files (x86)\\Micro Focus\\RM\\RMCOBOLv12\\runcobol.exe" /REGSERVER
64-bit: "C:\\Program Files\\Micro Focus\\RM\\RMCOBOLv12-64\\runcobol.exe" /REGSERVER
Or, re-install.
If it's on the network, please make sure the network share hosting the runtime is accessible.
The rmcbl12r.dll component is always located in one of the following two locations, depending on whether you have a 32-bit or 64-bit RM/COBOL system:
C:\\Program Files (x86)\\Common Files\\Micro Focus Shared\\RM\\rmcbl12r.dll
C:\\Program Files\\Common Files\\Micro Focus Shared\\RM\\rmcbl12r.dll
(Actually in %CommonProgramFiles(x86)% or %CommonProgramFiles% if this is not a EN system.)
If I'm guessing rmcbl12r.dll is present (can't imagine why it might be missing) but it can't load because something else it depends on is missing.
Finally, please check your anti-virus logs to make sure some rules update isn't blocking a component. It's unlikely but it has happened.