impdp failed to create PK constraints - ORA-14063: Unusable index exists on unique/primary constrain

Hi all,
First time posting so please forgive me if I break with protocol.

I need to rebuild some tablespaces in an 11.2.0.2 database with AUTOALLOCATE extents rather then UNIFORM extents.
I decided the best option was to build a new database and run a full export/import.

I exported my source database with the command:

expdp system/<pwd> full=y directory=dpdump_dir

dumpfile=expdp_full.dmp logfile=expdp_full.log flashback_time=systimestamp

 

Built a new database and pre-created all the tablespaces.

Then I imported to my target database with the command:

 impdp system/<pwd> full=y directory=dpdump_dir dumpfile=expdp_full.dmp logfile=impdp_full.log exclude=tablespace table_exists_action=append