https://scn.sap.com/thread/3757871
Hi Vikas,
Which version of AEX are you using? Make sure your NWDS version matches the PI/PO SP. And with the mentioned consideration use the pat 0 of NWDS for your build.
Is this the very first iFlow you are trying to create using your NWDS. If yes then check for the version and service pack. If you are having PO 7.4 SP 12 then only you can use NWDS 7.3 SP 17.
you may check for the above given thread as well.
Thanks,
Binod Kumar