Postgres BackUp and Restore: ERROR: duplicate key violates unique constraint "pg_largeobject_loid_pn_index"

Hi,

      I backup my database using the following command:

pg_dump.exe -f  Backup.sql  -U <username> -p <port> MYDB

       Now,before restoring, i drop all my tables,indexes,foreign key constraints.Then, i restore using the cmd below:


psql.exe -U <username> -p <port>-d MYDB -f Backup.sql

     The above results in following exception and the data is not getting restored:

ERROR:  duplicate key violates unique constraint "pg_largeobject_loid_pn_index"

      What else do i need to drop/delete to completely reinitialize my database ? Also, instead of dropping the tables,indexes,foreign key constraints, if drop the database and recreate it, the above error is not thrown.However, this approach is not an option for me due to some limitation in my application.

       Kindly help.

Thanks