The error message seems clear: master clear (MCLR, pin 1) needs to be connected to 5V.

If you want to keep MCLR disconnected, consult PIC's datasheet to see how to configure this option in FUSE bits. Additionally, confirm settings for using the internal crystal also in datasheet (I think high speed (HS) option is only for external crystal).

Proteus provides supply voltage to PIC implicitly. But @Mike is is correct about inserting a resistor between LED and the pin chosen to drive it.

Saludos!