Hi @JAEHYUN_HEO! Welcome to UiPath community! Which version of Excel are you using? This activity is known to have bugs with Excel 2010 and 2013, it’s mentioned here: Copy Sheet activity throwing exception - #8 by loginerror
Also, please check this solution to see if it helps:
Exception from HRESULT: 0x80010100 (RPC_E_SYS_CALL_FAILED) - #2 by loginerror