CASKC0018E Service (service-name) IDT load failed reason code: reason-code. The system attempted load the Interface Definition Table (IDT) for Service service-name. The file system open for the disk image failed with a reason code of reason-code. The reason-code will be displayed in decimal. The hexidecimal representation of the error might indicate a COBOL RTS error,
for example 0x390D is a 9/13 which means file not found.