hi irmus,
try this
serout PORTB.2,4,[$A0]

if this ones work, that mean you not declare :

INCLUDE "modedefs.bas" at the begining of your program

It appear that in some case that you must write PORTB.x in uppercase too.

Try also this :
DEFINE CHAR_PACING 1000

if this is not working tell me which PIC you use and how it is connected to RS-232 (with in serie resistor, thru an Max232...)


let us know !!!

regards