Which discipline of master degree involve ERP?

There should not be master degree solely designed for ERP since it's too specialized & differences exists among different brands & the scope is too wide.

Actually, you should make clear which scope you would like to develop in ERP-related industries.

1 stream is technical & another is operational.

For technical path, you may search for courses for database administrator & designer & maintenance which involve programming, with knowledge in hardware, software & networking e.g. MCSE

Another role in ERP administration & management is ERP project manager & adminstrator. They must possess good knowledge of business flow & IT knowledge. They are mainly responsible for streamlining business flow with ERP, solving user needs & problems, design of work flow & training users, auditing management data & reports from ERP, etc

Below is a course by HKUST:
http://www.cl3.ust.hk/chi/programs/program_open_detail.asp?selectBy=open&program_id=208