thank you for your reply ,
1- arcsde v 9.3 (32 bit) .
2- oracle v 11g r2 (32 bit) .
3- operating system windows server 2003 (32 bit)
NOTE : arcsde was installing before , and i need to re-installing again , i want ask about something ,when i remove arcsde program i drop sde user form database , but some geodatabse tables still remain in oracle database user schema , my questions is : if i must delete all geodatabse layers form oracle database ? , so i can installing new arcsde . may be this is the problem ?