Migrate/upgrade some users using export/import

Hi everybody,

I have a problem. I have an Oracle 9.2.0.1 Windows database that I want to migrate to 9.2.0.1 AIX. I'm using exp/imp procedure to migrate the data in two phases (I wrote the process below in this message ). It is very urgent for me to solve this problem, any answers to solve this problem will be very appreciated.
I don't want to import all users accounts, so I'm just creating a few accounts but in the process I'm receiving this IMPORT error:

...
"ALTER USER "VOLTRON" QUOTA UNLIMITED ON "TEMP" QUOTA UNLIMITED ON "OEM_REPOSITORY""
IMP-00003: se ha encontrado un error 1918 de ORACLE
ORA-01918: el usuario 'VOLTRON' no existe
. importando objetos de MAZINGER en MAZINGER
. importando objetos de AFRODITA en AFRODITA
IMP-00003: se ha encontrado un error 1435 de ORACLE
ORA-01435: este usuario no existe
. importando objetos de SYSTEM en SYSTEM
. importando objetos de WMSYS en WMSYS
. importando objetos de WKSYS en WKSYS
"ALTER SESSION SET CURRENT_SCHEMA= "WKSYS""
ORA-01435: este usuario no existe
. importando objetos de SYSTEM en SYSTEM
. importando objetos de WMSYS en WMSYS
. importando objetos de WKSYS en WKSYS
"ALTER SESSION SET CURRENT_SCHEMA= "WKSYS""
IMP-00003: se ha encontrado un error 1435 de ORACLE
ORA-01435: este usuario no existe
IMP-00000: La importaci¾n no ha terminado correctamente

As you can see the WKSYS user doesn't exists previosly in my database. Oracle fails after the command "ALTER SESSION SET CURRENT_SCHEMA= "WKSYS"", so errors IMP-00003, ORA-01435 and IMP-00000 appears.

How can I avoid this error stops the import process and continue importing the rest of the users accounts information?? I'm using the ignore=y clausule in the IMPORT command but the error stops the import process.
What can I do??
Do I need precreate all uses in the target database first???
Can I use import just for few accounts??

This is what I'm doing:

First,
1) I created the tablespaces in the target database
2) I created the users accounts in the target database. In this point I don't want to import all the users accounts in the new database so I'm just creating a few users accounts with their respective permissions.

After that I'm importing the information in two phases:

PHASE 1:

export ORACLE_SID=target

imp system/mazinger file=source.DMP buffer=300000 commit=y full=y rows=y indexes=n constraints=n grants=n ignore=y log=target.log

In this phase appears the error, so I cannot continue trying the second phase.

PHASE 2:

export ORACLE_SID=target

imp system/mazinger file=source.DMP buffer=300000 commit=y full=y rows=n indexes=y constraints=y grants=y ignore=y log=target2.log


Please note that this procedure have been working fine exporting/importing all users but not for a subset of the users accounts.
Any ideas to solve this problem??

Thanks in advance,
Regards.

If you don't want all users and since you already precreated the users ..use 'FROMUSER' and 'TOUSER' parameters. This way you can import single user objects at a time.(time consuming though)


imp system/mazinger file=source.DMP buffer=300000 commit=y fromuser=username touser=username rows=n indexes=y constraints=y grants=y ignore=y log=target2.log

I think that I need to determinate first what users grant privileges to others in order to import these users first. I think import one user at time can be a hard work.
I really will prefer migrate many users at time. In this case, the users of my choice. Something like IMP FROMUSER1=M1 TOUSER1=M2 FROMUSER2=Y1 TOUSER2=Y2 will be exactly what I'm looking for.
Thank you very much for your answer. I appreciate a lot your help.

Regards.