PIC + L6203 (Driver) problem (PIC Resetting)
!MCLR is floating. You must pull MCLR high through a resistor (4.7K for example) as it is an inverted reset line. Otherwise your application will mostly work until there is enough noise to drop MCLR and reset your PIC. Unless you specifically need to use the MCLR pin for something else, disabling MCLR in the fuses is also a bad idea, since it prevents the ICSP (debugger) from resetting your device after programming.