Hi,
The solution to the problem is first create the users in the new database as they were there in old database.Then create the tablespaces as the same names as they were in old database.Then import the dump file and go by user by user basis.It will be simple and more errorfree.

e.g
imp sys file=export.dmp log=a.log fromuser=a touser=a rows=y indexes=y grants=y constraints=y

The above command will import the tables assocaited with user a into user a.Perform the above steps with all the users.
Dont perform a FULL import of the dump file into the database.
Perform user-by-user import of the dump file.

In case of any help please be free to ask me at [email protected]

Regards,
Rohit Nirkhe,Oracle DBA,OCP 8i
[email protected]