importing oracle schema
The easiest way to import a complete schema to the database would be to drop the existing user/schema beforehand.

A simple:

drop user percon cascade;


...should be enough to have all objects that are related to your schema percon to be dropped before you continue with the import.

When you run the import you could just define the schema to import as suggested in a comment:

imp fromuser=percon touser=percon file=yourdump.dmp log=imp_percon.log


This should import all relevant percon schema/user data. If any errors occur you will find them in the log file.