Not understand. What exactly do You see after pressing *#06# - " IMEI not found" ?
"Telefono robado" (Espanol) = "Device rejected" (English) - do You see this message after phone trying to register in network? This probably happen, because string " IMEI not found", used in this patch for example ONLY, is NOT a "valid IMEI". Just set valid IMEI in patch, all 15 digits (14 IMEI numbers + 1 RIGHT checksum), for example:
0B6590: FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF 2031323334353631323132333435363000
in patch mean desired IMEI: 123456-12-123456-0
20 - " " - strongly needed!
31 - "1" - first digit of IMEI
32 - "2" - second digit of IMEI
..........
36 - "6" - last (14th) digit of IMEI
30 - "0" - IMEI checksum (shown as 15th digit of IMEI by pressing *#06#), here probably incorrect.
00 - 0x00 - end of string, strongly needed!
Please, post Your result!