ORA-15121
Oracle ASM file name 'string' contains an invalid disk group name.
Cause
A file name was specified that did not contain a valid disk group name. The disk group name follows immediately after the Oracle Automatic Storage Management (Oracle ASM) prefix character. It must start with an alphabetic character and consist of up to 30 characters which are alphabetic, numeric, or the characters '$' and '_'.
Action
Correct the file name specification.