After Import- Tables are missing

Hi Experts,

Yesterday i did my restore by export/import .
before importing i dropped allmytables,constraints,views,procedures,
synonyms ,sequences ,in my QA machine and imported from my
Production Database . After importing i found that 40 tables and 80 constraints are missing in my QA Database.may i know any specific reason why it is happening like this .please reply me.
Thanks in Advance.
Regards,
R.Rangarajan

Did you notice any errors in the import log.

You can perform it again with SHOW=Y, maybe that'll help you track the issue down.

Cheers,