A no. of errors are encountered while importing dump files in Oracle database.

Some of them are due to

1. Tablespace not found.
2. User/Role not found.
3. Incorrect database charset

If correct parameters are not provided to the person doing the import, it a more of HIT/TRIAL methdology.

A simple way out of these is to open the DMP files in any TEXT
editor,preferably VI if on Gnu/Linux and trying to read inbetween lines
to get some usefull info on the above issues.

Caution should be taken in
1. The dmp file if large will take time to load in the editor.
2. Do not edit the dump file in the editor, this might corrupt it,
preferable maintain a backup of the dump file before opening it in the
Editor.