first of all, thanks to steve and melanie for their feedback and help.
unfortunalety is doesn't work better.

i have this versions :
MicroCode Studio Plus 2.1.07
PicBasic Pro 2.44
MPASM 3.90 (updated today from 3.50)
melabs Serial Programmer 3.13 (updated today from 3.10)
firmware of the programmer 3.5 (updated today from 3.2)

my code is this :

@ __CONFIG _CONFIG1H, _OSCS_OFF_1H & _HSPLL_OSC_1H

DEFINE OSC 40

led var porta.0

init:
clear
TRISA = %00000000
PORTA = 0


main:
high led
pause 1000
low led
pause 1000

GOTO main

END

in the 18f242.inc file of the pbp root, i set line 20 as follow :
; __CONFIG _CONFIG1H, _OSCS_OFF_1H & _XT_OSC_1H

assembled with MPASM 3.90, getting no errors and no warnings. nothing.

problem : if i set the osc to 10, it works fine. when i set the osc to 40,
it works 4 times slower. (i work with a 10 mhz at a 18f242 and capacitors
with 22pf). in the melabs settings i test hs as osc as well as the hspll.
both settings have the same effect.

many thanks for any comment and idea...