Check and see if your rcie is being disabled.

Here is a code snip I use for the same thing.

;enable serial receive, part shows occasional disabling of receive
                SETB RP0        ;set bank 1
                setb rcie            ;on RCIF
                CLRB RP0        ;set bank 0
                jb ferr,rsr_1        ;reset rcsta on framming error
                jb oerr,rsr_1      ;reset rcsta on overrun error
                skip                    ;make sure cren is always on
rsr_1       clrb cren
                setb cren

Take care -Jim


>I use a PC to communicate with a 16C74 via RS-232.
>Sometimes after connecting the cable a get
>a framing error (FERR-bit2 of RCSTA chip register ).
>When this happens, no more data is received.
>Both RX and TX lines are high (on the chip).
>The manual states that FERR may be cleared by reading
>register RCREG. The only way I have been able to clear
>the FERR bit, is to reset the processor.
>I use the PICMASTER emulator and the following C-code
>is used for error handling:
>
>   if (FERR || OERR) {
>        CREN = 0;   /* Clear error */
>        CREN = 1;   /* Enable reception */
>        temp = RCREG;
>   }