These are the IPX and other OS services return values (0xFF01, 0xFF05, and 0xFF6A) that are defined in the NWDSERR.H file.:
0xFF01
ERR_OF_SOME_SORT: Many OS errors are originally 0xFF
0xFF05
ERR_REQUEST_UNKNOWN: Corresponds to OS error ERR_UNKNOWN_REQUEST which is 0xFB
0xFF6A
ERR_INSUFFICIENT_MEMORY: Corresponds to OS error ERR_NO_ALLOC_SPACE which is 0x96