i forgot to issue the command TFRJOB (QCTL) to our system after i ended all subsystem.
I assume you meant "before" ending all subsystems.
There shouldn't be any problem with an IPL if all subsystems were ended. It wastes some time, but that should be all.
If you need to transfer to QCTL, you should probably just logon to a device that allocates to QCTL. That makes it a lot harder to forget to transfer.