It's "LoadLibraryA", not "LoadlibralyA", and it's in kernel32, not ntdll. You need to look at IMPORTS for cabalmain. If I remember correctly, cabalmain already uses the LoadLibraryA function, so it should already be in the import table.
EDIT: I just looked at the "tutorial" you linked to, and it's complete poop. You don't need to copy the offset of a library function to call it... Imported functions get added to the IAT, and ollydbg has access to that, so all you have to do is double-click where you want to add the command and type "CALL Kernel32.LoadLibraryA" or "CALL LoadLibraryA". They both work.